When Anspaugh decides to retire as chief of staff and return to surgery, he appoints Romano as his replacement. Greene expresses reservations about the decision, but Weaver does not support Greene. Romano makes Weaver the new chief of emergency medicine.

After his mother's funeral, Dr. Greene comforts his father (JOHN CULLUM) in San Diego. In Chicago, Romano surprises Corday by appointing her associate chief of surgery. Corday treats Elaine, Carter's lover, for breast cancer.

A recommendation from Weaver allows Jeanie to have temporary approval as a foster parent for baby Carlos. Reggie and Jeanie get married. Lucy and Kovac talk with a young woman whose husband they believe is very dangerous.

Hathaway befriends an out-of-work waitress, Meg. Seven-months pregnant, Meg cannot afford prenatal care. Hathaway invites her to the hospital, performs free tests and helps her interview for a job in the cafeteria.

A prank in a high school science class goes terribly awry, injuring a teacher and several students. Hathaway discovers Meg's drug addiction. Weaver and Greene notice Lawrence gets easily confused.

Benton struggles with the idea of taking a DNA test to determine whether or not Reese is actually his son. As the signs continue to pile up, Kerry and Mark use a fake patient to convince Dr. Lawrence of his Alzheimer's. Carter has trouble persuading a woman from a nursing home fire to sign a DNR for her husband and later is asked to forge charts for a family with no insurance. Carol continues to meddle in Meg's life, having her arrested so that she can be detoxed. Cleo is blamed for an explosion in the suture room but it may actually be Dr. Dave's fault.

Weaver tries to save the life of a rape victim while Corday struggles with feelings of disdain as she is forced to save the rapist. Cleo treats a teenage alcoholic boy whose alcoholic mother refuses to recognize her problem or his.

On Thanksgiving Day Carol goes into labor. She's able to get to the ER only thanks to Luka's help. She delivers the first baby in the ER, but the second causes some trouble. Greene leaves Elizabeth to deal with his father and daughter, as he rushes to assist Carol.

Kovac and Haleh take care of Hathaway's twins so the new mother can finally get some rest. The job transfer for Carla's husband does not get approved allowing Reese to stay in Chicago. Lucy endeavors to get a heart transplant for a young woman and goes to Romano's house begging him to perform the surgery.

In order to get her patient to tell her the location of a missing body, Corday agrees to grant him a fatal wish. Kovac befriends two brothers. He tells Weaver that his wife and children died in the Bosnian war. Former medical student Deb Chen returns to County General as a resident, using her Chinese name, Jing-Mei Chen.

Lucy's patient finally gets the call to receive a heart transplant, but there are complications. Greene interferes in a gay couple's domestic situation. Corday tricked her patient who murdered several women and now he's being transferred to a county jail.

Two boys brought in after a fight at school leads Cleo to discover that one of them has a number of bruises and infected wounds. Hathaway's obstetrics nurse, Abby Lockhart, joins the ER as a third year medical student on an ER rotation.

Dr. Greene and Dr. Corday bond with their parents, Lucy cares for a patient with a psychotic break, and Valentine's Day celebrations in the ER end tragically.

Carter and Lucy are discovered and the staff struggles to save them and go on with normal patient care.

Kovac witnesses an accident and saves the young victim's life. Carter slowly recovers from his brutal attack and undergoes excruciating physical therapy. Hathaway helps two sexually active 14-year-old girls.

Even though he suffers from intense pain due to his stabbing injuries, Carter returns to work and prescribes a controversial procedure for a suicidal patient. Greene tries to convince his father to undergo cancer treatment.

Chen's patient refuses to reveal to his daughter that she might have inherited a terrible disease from him. Weaver defies Romano's authority and performs a procedure that gets her suspended. An available kidney causes friction between Corday and Kovac as they decide which one of their patients will get it.

After Corday refuses to perform exploratory surgery on Cleo's patient, Cleo enlists Benton's help, infuriating Corday. Abby cares for a pregnant woman with five children who wants an abortion. Greene lovingly tends to his dying father at home.

Carter seeks psychiatric help because he can't sleep. He then visits the wife of his attacker. Weaver returns to work after her suspension. Hathaway and Kovac share a kiss.

Weaver reprimands Carter for doing a dangerous procedure without consulting Kovac. She also talks to Hathaway about Hathaway's lack of focus on the job. And while treating a 6-year-old patient involved in a minor car accident, Malucci and Cleo discover the girl has been sexually molested recently by her father.

Greene prepares to bury his father. Chen worries about Carter's mood swings. After witnessing the interaction between a dying woman and her family, Hathaway realizes she wants her family together and flies to Seattle to join Ross.

As the result of a school shooting, Kovac and Benton care for the gunman and his victims. Abby discovers that Carter has been illegally injecting pain relievers. Greene and Weaver confront Carter about his problem, and Weaver orders him to enter a drug rehabilitation center or leave the hospital permanently.

Dr. Carter struggles with his drug dependency; a custodial strike leaves the ER cluttered with garbage; a riot at a high-school football game leaves several wounded.

A young couple cope with their baby being premature; Greene and Corday struggle with their relationship.

Dr. Carter is allowed a cautious restart with small steps. An extremely blond Dr. Malucci is very curious who's made Dr. Chen pregnant. Dr. Benton has been written out of all the hospital's systems and is stunned by Dr. Romano. An unfortunate incident at a Science Fiction convention makes it look like scenes from the movie 'Mars Attacks'.

Benton is unable to find a job after Romano negatively influences local hospitals. He reluctantly agrees to accept Romano's demeaning offer of a per diem job at County with no benefits. Kovac and Abby are attacked by a mugger with a steel pipe. Injured, Kovac protects Abby and smashes the robber's head on the ground repeatedly.

Greene flies in a helicopter to a remote area of Indiana to rescue a heart transplant patient. The helicopter develops problems, and Greene arranges for paramedics to transport the patient to County. Because Weaver is gone for the day, Romano appoints Benton in charge of the ER. Kovac is plagued by the death of the mugger.

Dr. Corday suggests a quick surgical procedure for a patient with back pain before taking off on a romantic weekend with Dr. Greene. Abby's mother, Maggie, unexpectedly visits the hospital and wreaks havoc on Abby's life. Dr. Chen needs the father of her baby to sign paperwork to go through with the adoption.

Abby's mother decides to stay in town; Carter attempts to find a drug addict who left the hospital: Greene discovers his health is failing.

Maggie's emotional instability worsens. She refuses her medication, becomes combative and flees the hospital. Abby finds solace with Kovac. The gang member girlfriend of Benton's deceased nephew knows who killed the dead boy who was hated for his antigang stance.

Chen gives birth, but insists on breastfeeding the infant before she gives it to the adoptive parents. Greene and Corday consult a brain specialist in New York City who believes the tumor can be safely removed. Stressed and tired, Carter impulsively swallows two painkiller pills but intentionally vomits them. He confesses to Abby.

Mark Green is in New York on New Years eve for cancer surgery. Meanwhile a father and son are involved in a car crash.

Benton and Cleo clash over his deceased nephew's girlfriend. They finally agree to call a social worker. Benton confesses his love to Cleo. The spinal surgery malpractice suit is settled by employing a technicality: the equipment used was later recalled by the manufacturer. But Corday now doubts her abilities as a surgeon.

Greene returns to work but confuses words and displays uncharacteristic anger. Eager to get out of his per diem situation, Benton agrees to a full-time position. Carter visits his cousin, who became paralyzed after a drug overdose. A workplace disaster results in numerous injuries and fatalities among illegal immigrants.

Weaver becomes concerned about Greene's cognitive skills and surreptitiously calls for an official evaluation of his competency. Corday plans her wedding to Greene. Bishop Stewart returns, and Kovac realizes the man has a terrible disease. Dateless for a charity function, Carter invites Abby to attend with him.

As the new director of diversity, Benton studies medical school applications and discovers that his own academic record did not qualify him--he was admitted because of affirmative action. Weaver feels uncomfortable amongst Legaspi's lesbian friends. Carter treats an unvaccinated child who contracted measles.

In the series' 150th episode, a massive train wreck mobilizes the emergency room doctors. Corday, Carter and Kovac rush to the scene. Corday falls and injures her back, bringing on contractions in only her 25th week of pregnancy. While amputating the legs of a fallen firefighter, Corday stops because of her pain.

Weaver fears for her own reputation when Legaspi is accused of sexual harassment. Afraid to reveal her relationship with Legaspi--for both personal and professional reasons--Weaver fails to support her during the investigation. An infant is abducted from the hospital and later found on a train platform.

A demented patient causes a shootout in the emergency room. After terrorizing people in the ER with a gun, she gets shot by a policeman. She soon dies. Benton later discover her dementia was caused by an aftereffect of his surgery that he and Cleo should have detected. Carter pursues a cute intern.

Numerous mishaps threaten to mar Corday and Greene's wedding day. As the very pregnant Corday becomes increasingly agitated, the presence of her bickering divorced parents does little to improve her mood. With the intense rain, Greene has a difficult time making it to the church. But, evenutally, he arrives and they joyfully wed.

Abby and Carter travel to Oklahoma to rescue Abby's mentally ill mother and bring her back to Chicago. In Chicago, Maggie suffers from a sleeping pills overdose. At County General, Kovac frantically revives her. Benton treats a college student injured in a fraternity prank.

Maggie contests Abby's attempt to institutionalize her. Weaver treats a few bizarre patients. When Legaspi returns to work after being exonerated of sexual harassment, Weaver tries to reconcile with her. Benton injures his hand while transporting his former teacher to the hospital and must contend with the teacher's wisecracking elderly buddies (TOM BOSLEY and TOM POSTON).

Cleo and Carla clash after Reese gets hurt while in Cleo's care. Weaver and Kovac cannot save the life of a developmentally challenged woman's only caregiver. Abby goes to a therapy session with Maggie. Later, Abby confesses to Maggie that she is afraid to bear children because they might be bipolar like her mother.

The ER is flooded with foster care home residents, attacked by a shooter bent on tracking down his son, who , with the help of Dr. Green, was put into the foster care system amid allegations he was being abused by his father.

Weaver returns to the emergency room after a self-imposed sabbatical of three weeks, wondering how her newfound lesbian identity will affect her workplace relationships. Having purposely allowed a mass murderer to die, Greene must keep the secret amidst the scrutiny of his superiors.

Carter is overwhelmed by patients from a rock concert riot. Benton's former girlfriend and Reece's mother is killed in a car accident. Newly promoted to chief resident, Chen panics and misdiagnoses a patient. Kovac angers Abby by flirting with a waitress.

Greene's daughter comes to live with him and Corday. Carter and Abby become more intimate. Chen must prove her skills while saving a baby. Weaver terminates Malucci after witnessing him having sex in an ambulance.

Dr. Susan Lewis arrives, looking for work in the Chicago area again. Greene hires her, over Weaver's objection. Chen nervously attends a risk management review, accompanied by the unforgiving Weaver, to discuss a patient who recently died under Chen's supervision.

Lewis faces a hectic first day back at County General. Benton and Roger become frantic when they can't locate Reese. Carter's grandmother is brought to the emergency room. Carter and Abby deal with inept medical students.

Corday's ordeal, caused by the recent infection-related deaths of several of her patients, worsens when she is closely observed by a stern taskmaster. Corday is outraged when a county investigator accuses her of deliberately euthanizing the patients, who all happened to be elderly.

A new medical student, Michael Gallant, arrives in the ER. He's supposed to be working under Dr. Carter's supervision but John's grandmother is unwell. Elizabeth Corday is convinced that other doctors are refusing to work with her as a result of the mysterious deaths. Mark Green thinks she's overreacting but she's determined to find out what happened to her patients. Abby and Luka argue over the attention he is paying to a trainee nurse's aide. Dr. Benton finds himself in court to retain custody of his son, Reese. Carter and Susan Lewis treat a young woman who is both a law and a medical student. Green has to collect his daughter at school when she is suspended.

When a torrential rainstorm pounds Chicago, patients deluge the emergency room while Weaver speeds to an accident site. There, she finds a pregnant woman, Vicki, lying injured inside a wrecked ambulance while live power lines spark. Fourth-year student Michael Gallant makes a dangerous decision in order to help.

Peter Benton continues his court fight against Reese's stepfather, Roger, who seems to have the upper hand. When a woman is accidentally shot during a gas station robbery, Dr. Corday tries to convince the husband to let them harvest her organs. A 15 year old boxer is brought in with a head trauma after sparring with his older brother. Newlyweds are having trouble when she constantly breaks out in a rash; Carter thinks he knows the cause. Luka tells Abby that he may marry Nicole, who has told him she is pregnant. Dr. Green lays down the law when the police bring in a high school student and he learns that his daughter is outside sitting in the police car.

Dr. Benton is awarded full custody and Roger receives visitation every other weekend.

Abby helps a distraught boy whose mother died of a stroke; a man with schizophrenia, who once stabbed Carter and killed a doctor, is brought into the ER.

An injured and condemned murderer wants to die in the ER rather than await execution; Abby advises a neighbor to seek shelter from her abusive husband.

An accidental overdose brings Drs. Green and Corday's baby into the ER.

Greene confronts Corday when she orders Rachel out of their home; Abby tries to protect a battered neighbor who refuses to press charges against her husband.

After Dr. Corday moves out, Dr. Green fights loneliness and pain by immersing himself into his work. Dr. Chen discovers that a comatose teen is ready to give birth.

After some staff members are caught going through a dominatrix's bag, Weaver makes them attend a sexual harassment seminar, where they learn about each other.

Drs. Corday and Greene are awkward when working together in the ER. Dr. Weaver treats victims of an intense fire that may take the life of a dear friend.

As Dr. Greene's brain tumor begins affecting his coordination, he becomes concerned that his fate will be similar to the terminally ill patients he treats.

When Dr. Lewis gets a hysterical call from her niece, Susie, she hurries to New York to search for the child and her sister Chloe.

Dr. Carter reads a letter from terminally ill Dr. Green to the ER staff. Dr. Weaver lashes out at a mentally challenged patient. A terminal, homeless man continues asking for Dr. Green.

Dr. Greene's final days are spent in Hawaii with Rachel, teaching her to drive and surf. When he suffers a seizure, Elizabeth is called. Mark refuses to go home. He manages to make amends with his daughter before his eventual death.

Just when the ER is understaffed and swamped, two children who were brought in turn out to have full blown smallpox. The entire ER must be locked down. The staff needs to improvise while they battle not only the disease but also frayed tempers.

Dr. Carter, Abby and other staff of the ER are quarantined as the CDC investigate a mysterious, deadly outbreak.

After another hospital shuts down, the ER is flooded with patients. Dr. Pratt resuscitates a heart-attack victim who had been pronounced dead.

Dr. Carter leads a walk-out of staff protesting lack of security in the ER.

Carter is concerned when he learns that Abby is drinking socially when the girls from work get together. Abby, however, doesn't appreciate his concern. Dr. Weaver embarrasses herself on television. Michael Gallant is frustrated when the resident cardiac specialist, Dr. Kayson, dismisses his diagnosis of a patient who subsequently dies. Dr. Pratt decides to report an Army Ranger who tried to commit suicide even though Gallant had decided to give the soldier the benefit of the doubt. Dr. Corday has to deal with a severely injured woman who is more concerned about her Alzheimer's-afflicted husband. Dr. Kovac's sex-addiction extends to having sex in a supply room with a young patient's mother.

On a busy Halloween night, Carter and Abby are the only staffers in costume when victims of an apartment building fire pack the ER. Corday takes on a new med student for a surgical rotation - Paul Nathan, who suffers from Parkinson's disease and decided to pursue medicine after being diagnosed. Despite a difficult first day, both professionally and medically, Nathan makes a difficult diagnosis. Romano's rehab lags behind his expectations, and he begins to think his role in surgery is no longer an option. In a moment of personal weakness, he tries to express his feelings for Corday. Weaver continues to display erratic behavior, raising staff suspicions about her menopause. Luka's burgeoning sex addiction worsens, as an affair with Chuny is revealed, and tensions rise when he treats a patient with a perpetual erection.

Corday clashes with new surgical resident Paul Nathan regarding his intervention into the treatment of a sickly young woman, Alison, who has signed a "do not resuscitate" order. Abby wonders about the erratic behavior of her visiting brother Eric, and feels conflicted over a nurse's official complaint against Kovac, Abby's former lover. Meanwhile, Pratt comforts Chen after a patient threatens her, and Corday suspects that an unconscious 14-year-old female patient has been sexually assaulted.

Abby fears the worst when her brother Eric suddenly disappears. He is actually AWOL and she forges Carter's name to obtain his medical records. Carter and Chen treat a frightened Chinese immigrant nanny, Tong-Yi, whom they suspect was impregnated by her employer. Meanwhile, new surgical resident Paul Nathan, who is struggling to overcome a physical disability (Parkinson's disease), tries to help in the emergency room but his fellow doctors do not appreciate his advice to patients. Unable to quench his sexual appetite, Kovac also gets into trouble in his professional life, despite his admirable resolve to find an eye specialist to treat a young gunshot victim. Gallant and fellow medical student Erin Harkins engage in an escalating competition of medical knowledge. And Weaver gets some much-needed good news.

Abby's family nightmare continues as she searches for her missing brother Eric, who she suspects is suffering from serious mental problems. Gallant accompanies her to his military base where they find Maggie, whom Eric turned to for help. When he's transferred, Abby and Maggie go to a Midwestern air force base, hoping to prevent Eric from being court-martialed for being absent without leave. Carter struggles to get out of Chicago to join Abby. Meanwhile, Corday treats a family of patients who, while building a snowman, were severely injured after being struck by a truck driver. She must help the father, Stuart, make a life-or-death decision. Corday also sympathizes with troubled surgical resident Paul Nathan as he struggles with the increasing symptoms of his physical handicap.

Harkins faces a tough call while treating a troubled teen involved in a car crash with her dad; Abby races to stop Maggie from taking manic-depressive Eric out of treatment; and Kovac hits a new low when an elderly woman tips him for his medical services. Meanwhile, an abandoned baby dredges up painful memories for Chen; and Pratt goes to bat for Leon after he's fired from his job for stealing.

Dr. Kovac's speeding causes a crash on an icy road. The ER staff treats angry elves and a female hockey player with a head injury.

Dr. Pratt brings a gun into the ER; Dr. Weaver tries to conceal her pregnancy; a woman plots against her dying husband; Dr. Chen treats math students who overdosed on an unknown stimulant.

Dr. Weaver is in a difficult situation when an alderman tests positive for syphilis. Dr. Carter is impressed when he meets a man who runs an inner city clinic.

Dr. Pratt's disabled roommate leads him to a wounded thief. Dr Carter decides to practice medicine in Chechnya. A doctor makes a pass at Dr. Corday.

Abby's troubled brother is missing. A car runs into a crowd of teen girls. The alderman with syphilis gives Dr. Weaver a promotion. Dr. Lewis looks forward to a blind date.

Abby comes close to breaking down trying to deal with her mother. Dr. Pratt goes for his required paramedic ride-along. Dr. Weaver confronts the man who stole her purse. Dr. Lewis has a teen admirer.

The police question Drs. Pratt and Gallant about a rampage at the diner across from the ER. Dr. Lewis befriends her teen admirer, a cancer patient.

Dr. Weaver bends the rules and treats the Alderman's lover for syphilis. Dr. Kovac's patient claims she was sexually abused at a boot camp for troubled youth. Dr. Carter treats a women with a nasty personality.

Dr. Romano seizes control of the ER and manages to offend everyone. Dr. Kovac asks Dr. Corday's help in the quest to bring a sickly Croatian boy to the U.S. for medical treatment.

A psychotic patient threatens Abby. Dr. Weaver suspects a woman poisoned her own baby. Dr. Romano continues to make rash judgments.

Dr. Carter tries to prevent a grieving gang member from going after vengeance. Dr. Kovac races against time to save a Croatian boy's life. A baseball player gets treatment for a heart problem.

It's Greg Pratt's last shift at County General and he treats a number of cases that were started by John Carter on the day shift. They treat a 12 year-old near drowning victim who has little chance of recovery; a Buddhist nun who has a special gift of seeing another's inner self; a woman who is convinced that the day's solar eclipse signals the end of the world; a drug addict who scams both of them for pain medication; and a pregnant woman who had her baby torn out of her womb. Dr. Romano has his re-attached arm amputated. Carter receives a call from Luka Kovac asking if he can come to the Congo and help out. Abby is none too pleased. Meanwhile, Doc Magoo's burns to the ground.

John Carter arrives in the Congo to find that Luka Kovac is away at a distant clinic administering vaccinations to the local population. He also finds appalling medical conditions. Too few nurses and doctors, limited equipment and few medical supplies are par for the course. That aside, he gets s great deal of satisfaction from the work he does. He meets Gillian, a Canadian nurse, and learns that she and Luka have become close. He tries desperately to save the life of a severely wounded man which pays later dividends when their camp is invaded by rebel troops and their lives are threatened.

On his return to Chicago, Carter gets a downright chilly reaction from Abby who asks him to return her apartment key. At work, they tip toe around one another, neither really willing to discuss their feelings. A new med student, Neela Rasgotra arrives for her ER rotation. Dr. Pratt is paying too much attention to her for Dr. Chen's taste. A woman passes out at the wheel of her car severely injuring herself and the three children in the car with her. Neela makes a good call in the case. Carter treats a man whose HIV has become full-blown AIDS. The ER itself is a bit chaotic due to major reconstruction. The ER desk receives a call from Africa saying that Luka Kovac has been killed. Carter decides to return to the Congo to retrieve his body.

John Carter returns to the Congo to retrieve Luka Kovac's body. He finds however that the area where was killed is still too dangerous to enter. He and Gillian finally manage to hitch a ride with a Red Cross worker, Debbie, who is going to the area. In flashbacks, we learn how Kovac and his fellow aid workers were taken prisoner by rebel troops. They are shot, one at a time, until only Luka is left. Amid the destruction of the eastern Congo, we learn his fate. Carter also makes a fateful decision.

Luka Kovac arrives safely at County General and is hospitalized for treatment. His friend Gillian delivers John Carter's letter to Abby. Pretty much everyone gets to read it when Frank retrieves it from the garbage and passes it around. Greg Pratt has dinner with Chen and her parents. The dinner goes well but they have a serious argument afterward. Dr. Romano is unhappy with his prosthetic arm which makes him even more difficult to deal with. Some of the more senior nurses find their hours being reduced as a cost-saving measure and stage a walkout. Romano's response is to fire them all. Dr. Lewis treats a teenager with a serious heart problem but her parents insist that she not be told immediately. A new group of second year residents arrive.

Confident second-year resident Pratt wants to prove his abilities when he works the graveyard shift (11 p.m. to 7 a.m.), but his heroics sometimes backfire. Pratt shows contempt for a man, Ed Gamble, who presents no symptoms of disease but temporarily loses his speech. Chen continues to get in the way of Neela's progress as her jealousy regarding Chief Playa Pratt's flirtations with everyone who wears a skirt reaches new levels of ridiculousness.

Emmy nominee Bob Newhart guests as Ben Hollander, a distraught architect whose degenerating eyesight causes him to be despondent while a spirited new nurse, Samantha Taggart, joins the staff. Elsewhere, disaster strikes when the doctors suspect a mother is abusing her child while Dr. Corday learns something shocking about the charismatic Dr. Dorset, and Dr. Archie Morris is overwhelmed by the chaos and grisly conditions of life in the E.R.

Pratt and Kovac clash over a miscarriage-prone young woman who arrives to deliver a premature baby. Pratt wants to make heroic efforts to save the unborn child, while Kovac is adamantly against spending vast amounts of money to keep the forever sickly baby alive.

To everyone's amazement, Lewis makes a date to share a home-cooked dinner with the elderly Ben Hollander, her depressed patient who is going blind.

On Thanksgiving Day, a helicopter crash outside the ER leaves several injured. Alex tries to bring Sam and Luka together.

Neela helps treat two Amish teens who were in a car crash. Sam argues with Dr. Kovac when he pays too much attention to her son.

Dr. Carter celebrates Christmas at a clinic in the Congo dealing with low supplies and anti-Americanism, but in the meantime, falling for an AIDS worker named Makemba.

Carter returns from Africa full of surprises including a new love, Makemba ("Kem"). Pratt accidentally breaks a patient's neck while doing an unsupervised intubation. A whole nursing shift cannot go home until they find one missing Valium.

Abby and Neela are assigned to a month-long rotation in the neonatal intensive care unit where they experience emotional roller coasters while caring for the sick infants.

Dr. Carter's girlfriend makes an impression as she observes ER operations. Dr. Gallant is almost shot during a domestic incident. Dr. Weaver dedicates a center to the memory of Dr. Romano.

Sam treats an abused, pregnant teen. Dr. Carter introduces African girlfriend Makemba to wintertime. ER chaos shocks a risk-assessment expert. Dr. Pratt and Abby restrain a man who has tuberculosis.

Carter misses his pregnant girlfriend who has returned to Africa. A family of four is rushed to the emergency room after suffering carbon monoxide poisoning from their faulty furnace--forcing the claustrophobic Neela to accompany a newborn baby into an extremely uncomfortable hyperbaric chamber.

Dr Morris agitates a patient who then leaves, steals a tank, and rampages through Chicago on his way to County General. He makes it all the way to the ambulance bay before the CPD finally stops him. Sam tries to figure out her relationship with Kovac while Gillian shows up at the ER to cement plans for dinner with Carter, Kem and Kovac - making things that much more difficult. Neela confronts Frank about his arrogant bigotry, bluntly telling him she wants nothing from him but silence from this point forward. During the initial onrush of patients due to the tank rampage, Frank has a heart attack which is, thankfully, caught. Frank's wife and daughter show up and are rushed up to the cath lab where Dr. Pratt is helping Dr. Kayson keep Frank alive. In the end, Neela winds up in the family room with Frank's family listening to them describe a side of Frank that no one has ever seen. Meanwhile Kovac treats a 13 year old with chlamydia and counsels him to contact his sexual partner - which turns out to be quite a few teenage girls.

Carter defends his protégé Neela when Weaver and other doctors rate the residents. Carter urges his student to be more proactive in the emergency room, but Neela goes too far in treating a patient with a brain injury--and sympathetic Gallant errs further by falsifying a medical report. Meanwhile, Chuck protects pregnant Lewis from a pervert who is harassing her. Kovac treats a disoriented young boy whose dad fears that tests will reveal he is not the boy's biological father. Chen is unable to find a caretaker for her combative father. And Corday is uneasy about dating two men at once.

Weaver rushes to the aid of her wife, Sandy Lopez, when the firefighter is severely injured while working and must now battle for her life. Frightened Weaver whispers hope to Sandy by reminding the victim of their newborn child.

Pratt struggles to diagnose a woman who suffers mysterious chronic seizures. An attractive woman, Campbell, informally accuses flirtatious Pratt of sexual harassment. Abby ponders how to get her contentious patients' attention during her psychiatric department rotation.

Carter greets the returning Kem, but their meeting with his father, Jack, gets tense after Carter announces plans for his grandmother's estate.

Carter takes Kem to the hospital to check on their baby since it's not kicking anymore.

Kovacs stops to help a woman and her son whose car broke down. Steve is getting close to Alex, and Sam panics. Abby is looking for her letter whether to see she passed her boards. Pratt shows off his new Chrysler. Elgin tries to build a connection between him and Pratt. Jing-Mei might be battered by her senile father.

After being shot at, Pratt, Jing-Mei and Elgin are trying to get out of their sinking car. Sam took Alex with her while fleeing from Steve. Kovac is considering going after them. Abby wants to go to bed since tomorrow is her first day as a doctor, but is thwarted by Weaver, whose custody battle might take a dramatic turn. A young drug dealer is brought in with "a foreign object" in her tunnel of life.

Neela is still struggling with her decision not to continue becoming a doctor. We discover that Ray is in a band. Kovac and Sam are in love, but where does that leave them?

It's a busy Fourth of July and Carter is the only attending working.

Carter, Pratt, Kovac and Abby are dealing with a woman and her three children who've jumped from the third floor of an apartment building to escape from the violent husband/father. Meanwhile Dr. Lewis becomes Chief of Emergency Medicine, Howard quits his internship and Dr. Corday is facing dismissal.

Neela starts a new job in the emergency room after working at the convenience store near the hospital. On Neela's first day, Pratt expects the interns, Abby, Ray and Neela, to take on a large patient load during their shifts. Pratt turns processing the patients into a competition, in which Ray is clearly going to be the winner.

An ex con and alcoholic patient, Charlie Metcalf (Ray Liotta) passes out in the waiting room and is brought to the emergency room by the doctors. It shows the real time of 45 minutes with an patient of his life story and his final days in the ER, which touches the doctors treating him.

A rape victim, barely able to speak, does all she can to help police find her attacker.

A wounded police officer's teenage son must make a life or death decision. Abby tries to convince a girl needing appendicitis surgery's parents not to transfer her and do the operation at County, but her father wants her transferred to another hospital due to his own trauma with surgery complications from years before.

Abby has a dialysis patient in critical condition, but she cannot find his physician, who does not want to be bothered during the holidays.

Gang members kidnap Abby hoping she can save one of their members with a gunshot wound. Ray starts treating a patient, but when she requests a new doctor, he gets offended.

Two teens enter the ER with gunshot wounds. When one dies, Neela botches telling the next of kin, making the woman hysterical.

When a 16-year-old girl who had received a kidney transplant from her father arrives at the emergency room feeling dizzy, Carter traces the problem to a new drug that the girl was taking to control seizures related to her kidney dysfunction.

While examining a young boy, Pratt finds a suspicious gash across his chest and calls Wendall for a consult. Kovac and Pratt examine a man who was shot when he confronted his boss with a gun. Jake tries to convince Abby to date him despite his being her student.

Dr. Weaver meets her birth mother, but their relationship changes when Kerry reveals she is gay. Dr. Carter causes a commotion when he confronts a couple hoping to scam some painkillers.

A soccer mom finds herself completely aware of everything going on around her, but is unable to move or speak after suffering a stroke.

Neela (who's in Chicago) and Gallant (who's in Iraq) miss each other and write letters. Gallant also tries to save the life of a little girl.

Sam's ex-husband shows up and wants to take Alex on a trip. Gallant is back and Neela hopes to see him before he goes back to Iraq.

A woman on a hunger strike refuses treatment until the INS give her son another deportation hearing. Abby searches for proof when she suspects a patient is the victim of elder abuse.

Jules 'Ruby' Rubadoux is back in the ER. He's still angry with Carter about the death of his wife.

Morris is named the new chief resident, which makes nobody really happy, except Morris. Meanwhile Luka and Sam are having communication problems, Carter gets a promotion Susan really wanted and Ray finds out a 14-year old who always comes in for free drugs has been raped.

After Carter finds out Kem's mother is hospitalized in Paris he decides to go there to tell Kem how he feels about her. Meanwhile, Ray makes a fatal error.

Casualties of a disaster flood the ER, which is short-handed because everyone is at Dr. Carter's going-away party because he's leaving the ER after 11 years. Dr. Pratt looks for the courage to confront his father, Charlie.

Sam and Luka go on the search for her runaway son, Alex. Meanwhile, Pratt and Lewis guide Abby, Neela and Ray, who have become R2's, on how to teach the new interns.

Ray objects when a surrogate mother in labor endangers the baby's life by not wanting to have a C-section. Meanwhile, Sam tells Luka that she and Alex are moving out; Pratt meets his half-brother and -sister; and Abby makes a difficult decision about a young boy.

Luka has a very bad day: New nurse manager Eve Peyton notices he doesn't want to work with Sam and tells him so. At the end of the day he's drunk and Abby takes him home.

The rainy night brings in diverse patients, including a mother involved in a car accident with her baby, a man with a satisfaction facilitator, and a comatose patient who suddenly wakes up. Also, Sam stands up to Eve and her strict ways and Jerry gets struck by lightning.

A new attending, Dr. Victor Clemente, comes aboard and quickly makes a stir in the ER. Abby's breast cancer patient convinces her to take a long awaited test. Luka befriends a young woman who awakes from a six-year coma. Also, Weaver shows Clemente who runs the ER.

Pratt's half-brother tries to get him to make amends with his estranged father. Clemente treats an infant chimpanzee and involves Abby and Neela on the secret case. Eve promotes Sam and her first task is to fire a beloved nurse.

A kidnapped girl is the victim of police shooting. Abby is stuck in the middle of a disagreement between Luka and Clemente. Neela receives a phone call from Iraq. Later, Luka and Abby share a kiss.

The ER prepares to take in victims from a plane crash while Neela and Pratt head out to the crash site where Neela makes heroic efforts. At the end of the day Neela gets a surprising visit.

Gallant impulsively asks Neela to marry him that exact day; she says I do but soon gets cold feet. Morris stands up to Weaver on a patient's course of treatment. Luka, Sam and Clemente treat a boy who contracted HIV from his mother. Also, Abby and Luka redefine their relationship and Luka is named the new Chief of Emergency Medicine.

Pratt and Weaver try to create a Christmas miracle when they work to save a girl wounded from gunfire. Eve gets into trouble after punching a disruptive patient. Also, Abby has a special gift for Luka.

Neela treats a religious teenage girl who turns out to be pregnant. Abby and Kovac struggle to figure out what to do with her unexpected pregnancy.

Ray helps an old friend escape from her abusive father. Dubenko volunteers in the ER but can't seem to handle a slow day. Abby and Kovac go baby shopping, while Neela gets unexpected and upsetting news from Gallant.

Dr. Nate Lennox, a former professor with ALS, is brought in as the progression of his disease is chronicled through his own flashbacks as he is treated by each of the doctors at one point. As Lennox wants to give up, Abby fights to convince him to keep on fighting.

An unexpected visitor puts Clemente in the middle of a domestic dispute. Meanwhile, Luka and Abby await test results on their unborn child; Neela struggles with her surgical elective and Pratt ends up with an unexpected suitor when he participates in a charity bachelor auction.

In Sudan, Carter and a colleague struggle to save a woman who was raped by a band of militants. Back in the ER, Clemente asks to return to work after the shooting incident, but Kovac refuses. Meanwhile, Neela and Pratt have a work dispute, and, in a related incident, K.J.'s father shows up again in the ER.

Weaver contemplates hip replacement surgery after she finds it hard to do her labor-intensive job. Meanwhile, Kovac tries to ease Abby's fears about raising a child together. Neela decides to attend a support group for military spouses but when she offers her opinions on the war, the meeting turns into a debate. And after Sam treats a fainting victim, she finds herself with an intriguing job offer.

Abby and Luka desperately try to keep a young woman alive who was brought into the ER with stab wounds to the neck. As her condition worsens, Clemente steps in and tries a risky procedure on her to save her life. Meanwhile, Neela pulls an all-nighter preparing to speak at a surgeons' convention; Ray treats a man who claims he has swallowed a bottle of pills; and Sam decides to take a part-time job with Richard to help with childcare expenses.

When two teens are in a car accident, Abby and Morris struggle to figure out what is wrong with the unconscious girl. Meanwhile, Neela gets a visit from her in-laws and discovers some troubling news. Kovac tells Abby that he plans to go to Africa and help Carter, but when he realizes Abby is not crazy about the idea, he decides to send someone else in his place. Sam starts her new job with Elliot and quickly starts to love the the perks.

Dr. Clemente's paranoia spirals out of control after he receives threatening mail from his girlfriend's husband. Abby senses something not right when a grandmother and granddaughter are brought into the ER. Sam's jailed ex-husband Steve is brought into the ER and everyone but Neela assumes he is faking sick. Meanwhile, tensions grow when Morris and Albright argue over a patient, Pratt heads to Africa to help Carter and quickly realizes how difficult life will be; Weaver finishes physical therapy.

Pratt gets to work in Darfur alongside Carter and his co-workers, but is troubled by great number of people needing care and finds himself making a dangerous journey.

Pratt struggles to get a straight story when two abused boys come into the ER with their father. Two U.S. Army officers enter the ER.

Chaos reigns in the ER when two prisoners are brought in for treatment, but instead plot a violent escape. Their desperate actions place one doctor in harm's way, and forces one nurse to become a tool in their plan.

Weaver, Kovac, and the other doctors work frantically to try to save Jerry and a pregnant Abby, who were both critically injured during the shootout that left the ER in shambles. Meanwhile, Sam tries to escape from her ex-boyfriend and his criminal accomplices as they head north, but things quickly turn violent.

As Abby and Luka cope with their newborn's life and death struggle, the couple is shocked to receive a surprise visitor: Abby's mother Maggie. Meanwhile, Sam fears the prospect of criminal charges; Neela discovers that Tony Gates will be joining the ER team as an intern and Morris gets his job back while Weaver gets demoted.

Gates is assigned to the case of a closeted gay man whose partner clashes with his family; Neela meets her new surgical chief, Dr. Crenshaw; and Pratt must cope with the flood of new interns.

Abby and Kovac discover both the joys and difficulties of raising a newborn; Morris is wrongfully accused of being a child molester; Pratt has his trial-by-fire when he has to handle the ER alone, juggling multiple traumas, teaching duties and a troublesome intern. Neela continues to be the target of her difficult supervisor, and Sam discovers her sons latest extra-curricular activity.

Curtis Ames, a carpenter who suffered a stroke under Kovac's care, sues him for malpractice. Kovac and Ames square off in court as each man's recollections of Ames' treatment are recounted via testimony and flashbacks. Meanwhile, Abby returns to work and must adjust to the dramatic changes in her life, and Pratt's early morning trip to the barbershop results in a new awareness of community need. Also, Abby and Pratt try an unconventional method for treating a heart patient and Neela tries a risky procedure which doesn't sit well with her chief.

Kovac anxiously awaits the verdict between himself and Curtis Ames but fears the worst. Meanwhile, Neela disobeys her chief's orders and also questions her feelings for Gates, and Weaver unwittingly steals the spotlight from Morris in his big television debut.

A belligerent young man who claims to have the flu turns out to be more than he seems, and presents a challenge to Morris and Sam when he refuses treatment. Abby's chance encounter with Curtis Ames leaves Kovac uneasy. Meanwhile, Pratt discovers a local church's risky drug exchange program, Neela and Gates square off, and Weaver gets an interesting offer.

A mysterious illness leaves little hope when a group of homeless kids enter the ER and one of them believes that Neela is a guardian angel in blue; Abby and Kovac clash over a possible case of domestic abuse; Pratt makes a shocking discovery about his brother, and Weaver is unexpectedly called into action when her television appearance becomes a real emergency.

Thanksgiving at County is quiet, with the normal number of routine (or nearly so) emergencies. But Abby makes up for the lack of excitement while returning to the hospital as the doctor on a helicopter transport.

Kovac and Gates treat a girl who appears to have been assaulted. When the police are no help with Ames, Kovac decides to confront the problem himself; Morris and other doctors work on a patient with an ice pick in his ear. Meanwhile, Ray tries to keep his new relationship a secret and Pratt can't fully deal when his half-brother officially comes out. Also, a new male nurse arrives.

It's Christmas in the ER. A homeless boy sends Gates and Ray on a mission. Meanwhile, in the ER, Neela oversees an unusual kidney transplant case; Sam takes a stand when a patient is dumped in an alley by another hospital; and Morris plays Santa for a special girl and learns the meaning of Christmas.

Weaver cares for a Katrina survivor who's reluctant to have surgery on her foot; budget cuts force Luka to make a difficult personnel decision. Also, Gates' home life intrudes on the ER; and Pratt and Hope are shaken after a patient in their care dies needlessly.

Kovac reacts negatively when he sees Abby giving extra attention to a patient; Ray and Gates clash over a patient, pinning Neela in the middle; and Ben takes things to the next level with Sam. Meanwhile, Pratt is under investigation and Weaver says a final goodbye to the ER.

Kovac finds himself in a tense confrontation with Curtis Ames, and Abby must act to protect her family. Meanwhile, Neela and Gates rush to get Meg to the hospital while Sam's new home is soon under threat from fire.

Abby and Sam try to treat an aspiring comedian with mysterious symptoms; Pratt must defend his actions in front of the medical board; Neela scrubs in on a kidney donor transplant; and Morris, as the lone attending, must run a busy ER. Also, Kovac gets a surprising proposal from Abby.

Kovac and Gates find themselves with a moral dilemma when a woman comes into the ER with acute liver failure; Neela finds herself questioning what is right when Manish decides to give up a kidney to a complete stranger. Meanwhile, Ray fights to get to the bottom of a cheerleader's accidental fall; Abby gets a prediction for her future; and Alex's troubles continue to intrude on Sam's work life.

A blizzard strands a family in the snow and Abby and Pratt quickly try to save the family. A gang shooting challenges Morris and Pratt. Meanwhile, Kovac and Abby begin making wedding plans, but their engagement might not be very secret; Gates struggles with the reappearance of his father and the possibility of losing Sarah; and Neela becomes jealous when Dubenko brings in a new surgical intern.

It's Sam's birthday, but she finds it hard to be away from her son Alex. Meanwhile, Sam meets a photographer taking pictures of a terminal patient and she gives Sam a new perspective on life. Dubenko's new surgical intern unsettles Neela during a trauma; Gates is shadowed by a new and nerdy intern and later must tell Sarah the truth that he may be her biological father. Also, Morris and Hope annoy Kovac and Abby when they try to help with their wedding preparations.

Kovac and Gates deal with a hopeless father whose son succumbs to heart failure; Pratt tries to resolve the tension between him and his brother; an Armenian man tries to be a good samaritan but ends up crashing near the ER; Abby sneaks in baby Joe when she worries his sickness may be worse than it seems; Also, Sam injures the instructor of a self-defense seminar.

In 12 hours, the ER will shut down. As Kovac is under pressure to take care of the patients before the final hours, he makes a pivotal decision about his future. Meanwhile, Sam befriends a photojournalist who returns only this time she's terminally ill; Pratt is concerned when his brother ends up in the ER drunk; Morris confronts Gates when he ignores his orders and angrily sends him home while Gates tries to defend his actions.

What is supposed to be a departmental dinner organized by Kovac turns out to be the surprise of a lifetime for Abby when she learns it's a surprise wedding, secretly planned by the eager groom. Meanwhile, at the wedding, ER staffers enjoy themselves with music and booze while Neela finds herself the center of unexpected attention between Gates and Ray, which leads to a drunken fight and a shocking conclusion.

The ER reopens with new changes. However, the ER is not the only thing that's changed; Kovac and Abby adjust to being newlyweds; Morris and Hope enjoy themselves at the honeymoon suite; Pratt attempts a change for a woman; Neela worries when Ray goes missing; Meanwhile, there's a new doctor in the ER and he means business; and another change may come when Kovac receives a phone call.

The ER is now in the hands of a new chief, Dr. Kevin Moretti, who is bent on major changes. Meanwhile, a phone call leads Neela to a hospital where a major shock awaits her, and a final farewell from a friend and colleague. Gates urgently goes home to stop Sarah from being taken away from him. A drug-addicted Iraq War veteran baffles Morris and Sam. Also, Kovac postpones the honeymoon and says goodbye to Abby and his son, for the meantime, while he travels to Croatia to visit his ailing father.

Moretti reassigns Gates back to the ER and treats a couple involved in a car accident. Morris prepares to take his written board exams. Neela is assigned a young genius intern. Kovac plans to extend his stay in Croatia while Abby struggles with single parenthood.

Gates and Julia nurture their newfound romance but are soon interrupted by a troubled phone call from Gates' ward, Sarah.

Dr Wexlar is made interim ER chief while staff deals with an industrial accident that leads to a hate crime.

Morning shift begins. The night shift treated 142 patients - a new record. Dr. Morris is confident that by the end of the day the ER can set a new record of 300 patients. Frank reminds him that there has never been more than 250 patients in a day. Dr. Morris bets $300 that they can reach 300 by the end of the shift. Frank, Dr. Gates and Dr. Pratt each bet $100 against him. But will the game be fair? Also, when chaplain Dupree arrives announcing that she's doing a round of the hospital, holding blessing ceremonies and memorials, the guys are against it, except for Dr. Gates, which makes the others suspicious. Frank goes straight to the point. Then there is the accident involving a camel.

Abby deals with her upcoming reunion with Luka in Croatia, a heart transplant patient is admitted when her body rejects the new heart, and a new doctor ruffles feathers.

Abby returns to work; Luka applies for a job elsewhere; the reason behind a brash doctor's being at County is revealed.

In the season finale, an ER patient with a mysterious past is afraid that people are trying to kill him. Dr. Moretti returns, trying to make amends for wrecking the marriage of Abby and Luka. Neela makes her way through a difficult M&M conference. Morris treats a woman with lupus who has an attractive daughter.

When a gunshot wound victim arrives, the new chief and Abby butt heads on how to treat the patient. Abby comes to Sam's defense when she goes before a nurses disciplinary board.

Curtis Ames, a carpenter who suffered a stroke under Kovac's care, sues him for malpractice. Kovac and Ames square off in court as each man's recollections of Ames' treatment are recounted via testimony and flashbacks. Meanwhile, Abby returns to work and must adjust to the dramatic changes in her life, and Pratt's early morning trip to the barbershop results in a new awareness of community need. Also, Abby and Pratt try an unconventional method for treating a heart patient and Neela tries a risky procedure which doesn't sit well with her chief.

A new attending, Dr. Victor Clemente, comes aboard and quickly makes a stir in the ER. Abby's breast cancer patient convinces her to take a long awaited test. Luka befriends a young woman who awakes from a six-year coma. Also, Weaver shows Clemente who runs the ER.

Kovac and Gates deal with a hopeless father whose son succumbs to heart failure; Pratt tries to resolve the tension between him and his brother; an Armenian man tries to be a good samaritan but ends up crashing near the ER; Abby sneaks in baby Joe when she worries his sickness may be worse than it seems; Also, Sam injures the instructor of a self-defense seminar.

As the new director of diversity, Benton studies medical school applications and discovers that his own academic record did not qualify him--he was admitted because of affirmative action. Weaver feels uncomfortable amongst Legaspi's lesbian friends. Carter treats an unvaccinated child who contracted measles.

Benton is unable to find a job after Romano negatively influences local hospitals. He reluctantly agrees to accept Romano's demeaning offer of a per diem job at County with no benefits. Kovac and Abby are attacked by a mugger with a steel pipe. Injured, Kovac protects Abby and smashes the robber's head on the ground repeatedly.

Chen's patient refuses to reveal to his daughter that she might have inherited a terrible disease from him. Weaver defies Romano's authority and performs a procedure that gets her suspended. An available kidney causes friction between Corday and Kovac as they decide which one of their patients will get it.

In the series' 150th episode, a massive train wreck mobilizes the emergency room doctors. Corday, Carter and Kovac rush to the scene. Corday falls and injures her back, bringing on contractions in only her 25th week of pregnancy. While amputating the legs of a fallen firefighter, Corday stops because of her pain.

Dr. Kovac's speeding causes a crash on an icy road. The ER staff treats angry elves and a female hockey player with a head injury.

In order to get her patient to tell her the location of a missing body, Corday agrees to grant him a fatal wish. Kovac befriends two brothers. He tells Weaver that his wife and children died in the Bosnian war. Former medical student Deb Chen returns to County General as a resident, using her Chinese name, Jing-Mei Chen.

Kovac finds himself in a tense confrontation with Curtis Ames, and Abby must act to protect her family. Meanwhile, Neela and Gates rush to get Meg to the hospital while Sam's new home is soon under threat from fire.