Mark Greene's wife Jen gets a position clerking with a Federal judge. Unfortunately, it's in Milwaukee, 2 hours away and she wants Mark to look for a job there. Greene and Susan Lewis treat Samuel Gasner, a man who has been waiting for a heart transplant and who will not survive the night unless a donor can be found. John Carter is worried that his latest paramour may have left him with a souvenir of their sexual encounter. Doug Ross treats a young girl suffering from severe asthma but whose mother can't afford her medication. Benton treats Ivan the liquor store owner who is shot for the third time in as many weeks.

The realities of the ER may be too much for a child, but circumstances force Greene to bring his daughter Rachel with him on a day when the outdoor temperature tops 100 degrees and the air-conditioning doesn't work. Benton and Langworthy try in vain to save a boy shot in self-defense. Meanwhile, Lewis's broke sister, Chloe, steals Lewis's TV and VCR. After Ross crosses the line with Hathaway and Taglieri, Hathaway slugs Ross.

The ER staff's slow snow day becomes chaotically hectic when the casualties of a 40 car traffic accident flood in.

Susan Lewis has a run-in with Dr. Jack Kayson, the cardiology attending, when he accuses her of not providing him with all necessary information on a patient who subsequently died. He makes it very clear that Susan will bear all responsibility for his death. Her sister Chloe informs her that she and her boyfriend are moving to Texas. John Carter is still frustrated by Peter Benton's apparent lack of interest in teaching him anything but a new go for it attitude leads to an invitation to assist in a surgical procedure. Benton's sister suggests to him that the time has come for them to put their mother in a care home.

Benton is called out of surgery to find his senile mother.

Dr. Kayson becomes Lewis' patient.

Dr. Greene gets offered a new job by Morgenstern.

Kayson, a married man, tries to start a romance with Susan by asking her to dinner. Deb unknowingly eats LSD-laced chocolates. Carol takes an interest in a Russian girl abandoned in the ER.

It's a day of birthdays. Peter Benton's mother is celebrating a birthday and he tries desperately to find someone to cover his shift. He makes a choice however when Dr. Hicks suggests that he's been absent too often and may wish to consider a leave of absence until his mother's situation is resolved. Carter thinks it's Benton birthday and has a surprise for him. Mark Greene's daughter is also having a birthday but he misses that due to an emergency at the hospital. An elderly, solitary man in the final stages of cancer arrives in the ER on his birthday. Carol Hathaway suggests to her fiancé that they adopt little Tatiana, the AIDS patient abandoned in the ER. Ross has to deal with a young child who was kicked out of a window.

Dr. Greene is still haunted by the death of Jodi O'Brien and isn't sure he can function as a doctor. At Susan's urging, he takes the night off but unfortunately for him, the new head of the ER Dr. 'Wild Willy' Swift arrives unannounced. Susan impresses Swift with her handling of many cases on a busy night. She also has to deal with the case of a young man who has had the hiccups for two days but may in fact be suffering from something far more serious. Nurse Hathaway and fiancée Tag are still working out the details of their wedding. Peter Benton's mother is still hospitalized and he will not accept that her age and her injuries mean that she will need permanent nursing care. Dr. Ross is now dating Diane Leeds. John Carter and Deb Chen's attempts at oneupmanship is starting to take on ridiculous proportions.

Dr. Greene is still having trouble dealing with cases in the ER and the new Chief of the ER is growing increasingly concerned. Greene also faces a difficult peer review to examine his handling of the Jodi O'Brien case. Dr. Benton takes on the difficult task of telling his mother that she must be placed in a home with full-time care. Susan's very pregnant sister Chloe returns to live with her. Dr. Ross deals with the case of a young girl with a heart condition while Ross and Carter encounter a patient who refuses treatment for tuberculosis. When Benton asks Deb Chen and Carter to submit their procedures book in a few days, Deb feels she has to get a few more procedures under her belt if she's to best her fellow student. Unfortunately, her eagerness leads to near tragedy for a patient.

Greene finds his marriage falling apart and is concerned at how little time he's spending with his daughter. He also treats an eight week old child with a heart murmur who requires surgery. Susan tries to get her pregnant sister Chloe to take her pregnancy seriously, but her head isn't quite into it. Benton tries desperately to find a surgeon who will operate on a 16 year-old with a severe brain aneurysm that could burst at any time. He's also concerned at his mother's care and is growing ever more attracted to Jeanie Boulet. Doug Ross' commitment to Diane Leeds gets more serious when he agrees to be an assistant coach for her son's little league baseball team.

On a fateful Mother's Day, several staffers in the ER face possible life-changing events. Susan Lewis' sister Chloe gives birth to a beautiful - and healthy - baby girl. Things start to go wrong however when their mother Cookie - who had agreed to take in Chloe and the baby - suddenly decides she's done enough and Susan will have to take care of it. Carter turns down an offer for an ER sub-internship in the hopes that he'll get an offer in surgery. Dr. Hicks has news for him however. Benton's mother takes a turn for the worse. Carol Hathaway is overwhelmed with the final preparations as her wedding day approaches.

It's Carter's last day in the ER and finally fed up with Dr. Benton's apparent indifference, rejoices when he learns that he gets to write an appraisal on him. He subsequently regrets his negative input when he gets offered the surgical sub-internship he'd hoped for and learns that Benton gave him a glowing appraisal. He also spends a good part of the day with young leukemia victim who is fed up with life. Benton and Jeanie Boulet's relationship reaches a crossroads. Mark Greene is offered an attending position at the hospital but also learns that he is being sued for malpractice over his handling of the Jodi O'Brien case. The big day for Carol Hathaway and Tag is here but doubts creep in and one of them gets left standing at the altar.

While victims of a gang shootout are being brought in, Carter is late and a new group of third year medical students arrives.

It's Weaver's first day and she doesn't exactly make a lot of friends. Carol rides along with the paramedics.

The feud between Susan and Weaver gets to the point where Mark has to step in.

Doug and Harper had sex. Mark finds out about this. So does Carter.

Doug gets the opportunity to stay at the ER thanks to the publicity surrounding his rescue of a drowning boy the week before.

Jennifer and Rachel have been involved in a car accident and Mark rushes to Milwaukee where they're in the hospital.

Mark has to deal with the fact he can't see Rachel during the holidays and takes care of a Holocaust survivor whose grandchild is missing.

Rumour has it there's something going on between Mark and Susan while Benton questions Vucelich's study and confronts him.

Shep and Raul go in a burning house without the proper equipment to save three children.

Mark has to work for the fourth night in a row while a lot of the staff are absent and the number of patients is towering.

Benton dismisses a patient he hasn't seen who should have been admitted. Carter competes with Dale, a new surgical resident-in-training who once slept with Harper.

Susan has therapy to get over losing little Susie and Jeanie's ex-husband is brought in.

Mark Greene strikes a deal with Kerry Weaver - he will support her application for an ER attending position if she in turn will support Susan Lewis for Chief Resident. When Susan doesn't get the job, Mark is told to go ask her why. Carter is finally going to graduate and wants Benton to attend the party his family is throwing for him. Unfortunately, Carter decides to sit with a young patient awaiting a liver transplant and misses his own graduation ceremony. With the news she has received about her former husband Al's health, Jeanie Boulet decides to have herself tested. Doug Ross' girlfriend Karen forges his prescription for percodan. Hathaway's boyfriend, Shep, is refusing to undergo his anger management treatment. Mark's ex-wife Jen tells him that she is going to re-marry. Loretta Sweet asks Greene if he would become guardian to her kids.

It's the first day of Carter's internship. He has a 36 hour shift and overnight he has to cover the ER, the ICU as well as the surgical patients.

While the whole staff is worried the ER might close, Jeanie has her own problems in dealing with being HIV-positive.

Donald Anspaugh has a new method to increase the staff's efficiency, new intern Maggie Doyle joins the ER and Susan asks Mark to come along to Hawaii.

While Mark is anxious about Susan's return from her holiday, Doug and Carol ride along with the health mobile.

While on their helicopter flight rotation, Mark and Susan find an injured family of four who they bring to the ER.

Encouraged by Carol, Mark finally asks Susan out. Benton tries to save a boy, despite the fact Doug thinks he's brain dead.

It's Susan's last day. Carol stands up for her nurses when one of them is being rotated to another department.

Mark and Kerry have to create a policy regarding HIV-positive employees, which leads to gossip amongst the nurses.

Carol has to fire two of the nurses. Meanwhile, Gant feels Benton is too hard on him.

Carter feels guilty about Gant's death. Benton doesn't want to talk about it.

Doug treats a dying 17-year old cystic fibrosis patient who doesn't want to be resuscitated. Carter gets to operate on Benton.

Race relations become an issue in the ER when Mark Greene treats two injured teenagers, one black and the other white, and assumes the black kid was a drug dealer. It turns the white kid was the drug dealer and the black kid is a high school basketball star and an innocent bystander. When the black student's older brother confronts him, he begins to question his own impartiality. Carol Hathaway helps a young woman who was drugged with Rohipnol and raped. Benton gets an interesting offer from Dr. Hicks. He also learns that Carla Reece has been admitted to the hospital. Dr. Carter treats a woman with a serious condition but he seems to be the only one who sees it. Mark Greene's daughter ends up spending the day in the ER when her mom has to rush to Florida to deal with a family emergency.

Benton tries to find out if everything's OK with Carla's baby. Carter tries to get a man operated, despite the fact Anspaugh thinks he will die no matter what.

Benton takes a day off to help Carla. Carter finds out Edson falsified a chart.

Jeanie asks Greg to help Al get into a special AIDS-program at the hospital. Olbes brings in her grandfather, who had a stroke.

It's Carol's birthday, Mark is returning to work after being assaulted and Carla goes into premature labor.

While a film crew is filming in the ER, it's Elizabeth Corday's first day.

Cynthia Hooper starts as the new desk clerk. Benton and Carla disagree over whether or not their son should be circumcised. Al gets in an accident at work.

His ex-wife Jennifer tells Mark he can't see Rachel until he's got his act together. Reece gets to go home. Al has lost his job.

Al wants to move to Atlanta where he got a job offer. Jeanie however isn't keen on moving. Carol talks to Carter's grandmother about the clinic.

Benton has a very extraordinary and interesting case when he comes across a boy with reversed internal organs.

Jeanie believes she's been fired because she has HIV and fights her dismissal.

Mark treats an old lady who has been brutally raped. Carter's grandmother visits Carol's clinic. After he's touched by Benton, a blind man can see again!

Kerry starts to doubt the methods of Synergix. Carter tries to help his cousin beat his drug addiction. Jeanie becomes Scott Anspaugh's part-time caregiver.

Another elderly rape victim is brought in. So is the rapist.

Because of benzene that's been spread, the ER has to close. Weaver gets felled and Carter has to take the lead.

Mark finds out Cynthia has moved. Carter's cousin Chase is brought in because of a heroin overdose. Doug and Kerry clash after she found a flaw in his study.

Following the incident in the OR, Dr. Morgenstern and Dr. Benton present the case to their colleagues. As a result, Peter Benton finds himself suspended for insubordination pending a full inquiry. Jeanie attends Scott Anspaugh's funeral and has some information to share with the boy's father. Anna Del Amico finds herself ethically unable to perform an abortion and is taken to task by Dr. Weaver. John Carter gets the hospital to take legal guardianship of a patient he feels has been subjected to elder abuse, but subsequently doubts that he made the right decision.

Benton and Elizabeth Corday spend the night together. Corday is shocked when Robert Romano suggests that they go out on a date. John Carter and his grandmother clash over the future of Chase Carter; she wants him cared for at home while John feels he should remain institutionalized where he can continue to receive therapy. Carol Hathaway finally gets around to inviting her mother to a Sunday brunch with her and Doug but is a bit surprised when she shows up with her boyfriend. In the ER, Hathaway comforts a man who is going to die from chemical burns.

Assisted by Carol Hathaway, Doug Ross decides to detoxify a drug-addicted infant in the ER without telling anyone. Jeanie Boulet is feeling rundown and fears that her health may be deteriorating. John Carter is less than pleased when Anna Del Amico's former boyfriend shows up in the ER conducting a study on the need for a pediatric attending physician. Del Amico also has to treat a televangelist who is using her health issues to raise money. Elizabeth Corday is worried that Rocket Romano may be aware of her affair with Peter Benton and that it will affect her fellowship.

At the hospital daycare, one of the child-care workers suggests to Peter Benton that he may want to have baby Reece's hearing checked. Doug Ross dodges a bullet by admitting upfront his error in detoxifying a baby without permission. Having been acting Chief for over 6 months, Kerry Weaver puts her name forward to replace David Morgenstern as Chief of Emergency Medicine only to be told she will have to compete for the job. The doctors treat a couple of Elvis impersonators who sky dive into Lake Michigan. When drugs go missing from the ER, John Carter suspects Anna Del Amico's ex-boyfriend.

Third-year med student Lucy Knight reports to the ER for the first day of her rotation. Greene takes a paternal interest in her, helping her get acquainted, but she gets off to a bad start with the irritable Carter. The rest of the day finds her informing a wife of her husband's terminal condition, comforting a pregnant woman, getting locked on the roof and trying to figure out Weaver's "Tour on Tape."

To save rent money, Carter lives in a medical student dormitory as a resident advisor. While visiting Corday at her apartment, Benton meets her father.

Benton performs dangerous surgery on a bomb-carrying man who was shot at a factory. Dr. Ross receives some good news that Dr. Weaver doesn't embrace, but she has no recourse. Rachel encourages Dr. Greene to help a horse that is in pain. Jeanie Boulet returns from her vacation.

Lucy finally admits to Carter that she doesn't know how to start an IV. Weaver interviews for the job as the ER Chief. Benton keeps his son's disease a secret. Jeanie intervenes when she finds out a liver transplant candidate is drinking again, and later asks Doug if she can be assigned to work for his pedes project in the ER. Corday gets stuck as the intern of dismissive and insulting Dr. Dale Edson.

It's Halloween in the ER, and the medical students throw a party; as a result, Carter decides that Lucy isn't mature enough to take responsibilities. A candidate for the ER Chief position arrives from New York and drives home disappointment for Kerry. Mark screws up when he doesn't recognize a homeless schizophrenic woman is pregnant before treating her. Benton treats Corday to a fun Halloween.

Corday faces M&M where the board was discussing the mistake that Corday made after she gave the wrong dosage to a patient. She decides to take the offensive and let the board know how wrong it is for her or any other doctor to work 36 hours. The board decides to do nothing about it, and she later decides to amicably end her relationship with Benton. At the hospital arrives Ruth Johnson who was born 100 years ago in that same hospital and shares some experiences with Carter. Carol is horrified by the truth behind a young boy's fatal shooting.

Dr. Greene tries to help get Amanda Lee the proper credit she deserves on a paper she wrote. However, he starts to become suspicious of her credentials. An old friend of Dr. Greene recommends him for a NASA mission. Benton's son is having difficulties in day care. Doug and Carol help the exhausted mother named Joi of a little boy named Ricky who has a terminal illness. Carter is jealous when Lucy goes on a date with Dale.

Lucy begins her surgical rotation under Benton and Corday. Romano offers to get Corday's fellowship reinstated and asks her to assist him in surgery. Weaver interrogates Corday, asking if Romano ever sexually harassed her. Corday denies it and concludes that Doyle must have filed charges. Ross jeopardizes a liquid pain medicine study by surreptitiously giving some of the drug to Joi's son, Ricky. Greene discovers the secret and informs Weaver. They decide not to tell Anspaugh because, by violating protocol on a federally-funded trial, the hospital would be unable to obtain research money and Medicare payments for years.

When a school bus becomes involved in an accident, Mark assists paramedics with treating injured children; Weaver makes a discovery regarding a colleague.

Carter deals with tenant drama at an apartment tower during a ride-along that later has deadly consequences, Lucy has to hide a cancer diagnosis from an ill woman at the behest of the patient's family, Carol finds out she is pregnant, Kerry reflects on her own family issues when an injured wrestler comes to the ER, and Greene continues to help Mobalage, who may be deported if he can't tell the INS about the abuse he suffered in Nigeria.

Carter mentors a talented teen from a very rough neighborhood. Romano is upset about Benton's interest in the fellowship. Lucy continues impressive work in her Psych rotation, treating a law student with homicidal impulses and an angry youngster who is being severely over-medicated. Jeanie continues to grapple with her Hepatitis-C but gets a huge boost from a kindly minister. Hathaway reveals she is pregnant after a kid kicks her in the stomach, risking her baby. Greene and Corday attempt to go to a ball for trauma physicians but end up getting lost repeatedly while having a lot of fun hanging out together.

Romano observes the ER, and rubs the staff the wrong way. Lucy finds out that an elderly patient's bedsore is really much more. Carter breaks up with his girlfriend. The power goes out at County General, and the doctors must keep critical patients alive. Corday investigates the rape of a comatose patient.

The ER has to deal with a stripper and some shady dealings from apparent FBI agents. Lucy reveals to Carter that she's still on Ritalin. Hathaway begins to reveal her pregnancy to those closest to her, including a fax to Doug. Dr. Anspaugh decides that the trauma fellowship will go to Benton, who then faces anger from Romano and Corday. A car accident involving teenagers may have been alcohol-related and leaves one teenager with grievous third-degree burns.

The rest of the staff finds out that Hathaway is pregnant. Benton begins a custody battle for his son when Carla Reese reveals an intention to marry Roger and take the child to Germany. Weaver rescues a toddler that has been drugged. Carter's protégé is mugged and beaten up. Greene and Corday fall in love.

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.

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.

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.

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.

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.

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.

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.

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.

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).

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.

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.

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.

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.

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.

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.

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.

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

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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?

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.

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.

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.

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.

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.

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.

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.

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 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.

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.

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.

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.

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.

Abby, Pratt and Morris clash with Moretti's strict new ER procedures as victims of an anti-war rally roll in, including Neela. Gates manhandles a patient he suspects set off the explosion that disrupted the protest. A worried Dubenko lets his emotions for Neela take over during Neela's surgery. Meanwhile, the rest of the staff worry over Neela's condition.

The city suffers power outages during an unseasonably hot spell. Nursing-home patients are brought into the ER suffering from hyperthermia. Abby and Pratt disagree on the diagnosis of a fussy baby. Abby falls back to old habits and quickly spirals down to rock bottom on a night she'll forever regret.

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

Pratt gets cold feet when Bettina tries to take their relationship to the next level. Neela joins the Ortho's hockey team and is shocked to see who their opponents are in the first game.

The ER is on guard as Gates gathers the new interns to treat a terrorist, but it's the new doctor and her tough disposition that has everyone on the defensive.

Trying to rescue a three-year-old girl from drowning in a nearby lake, Banfield is reminded of her own experience at County with Dr. Greene caring for her son.

A single mother is hurt in a car accident, and must find someone to take care of her daughter. Gates treats a 78-year-old man who refuses surgery that would save his life. Meanwhile Morris's afternoon date with Claudia is not what he expected.

Dr. Carter returns to Chicago and talks Dr. Banfield into allowing him to pick up a number of shifts (without pay). Other happenings include Banfield's dogged pursuit of motherhood, Neela's intensifying personal relationship, and Archie's involvement with a patient who was probably beaten while in police custody - with his new girlfriend the detective standing by.

Banfield and her husband look into adoption, while Carter adjusts to a changed ER. Sam's mother comes into the ER in an altered state of mind.

Carter's illness overtakes him during a critical procedure in a trauma room as a documentary film crew spends the day interviewing the health care givers.

A girl drops off a sick baby at the ER and then leaves; Carter may get a kidney transplant; Gates and Daria care for an elderly woman with multiple sclerosis; Neela and Sam are in Seattle to transport a heart for Joanie Moore, while Doug and Carol are concerned that the donor's grandmother might not consent.

As Carter prepares to open a new facility for the underprivileged, some old friends/colleagues gather. Rachel Greene, Mark Greene's daughter, applies for an internship at County.