Carter gets his first official patient while Doug treats a four-year-old Asian boy who has AIDS.

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

Doug treats dying Chia-Chia. Mark however feels he's not doing the right thing for Chia-Chia.

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

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.

Shep and Raul enter a house with about a dozen abandoned and ill-fed children and bring them to the ER.

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.

In order to avoid having to deal with her personal problems regarding little Susie, Susan wholly absorbs herself in her work.

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.

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

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

Carol worries about her physics exam while Mark is heart-broken about Susan's departure and focuses solely on his job.

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.

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.

Carter is excited about getting his own med student, and Mark and Carol interview candidates for the desk clerk position.

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!

Dr. Anspaugh's 13-year-old son is brought in and Anspaugh asks Mark to look after him. Another old lady who has been raped is brought in.

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

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.

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.

Ross helps the mother of a dying boy; Benton attends a parent/child signing class. Corday doesn't give her account in the case against Dr. Romano. Romano blackmails Corday into dropping her support for Doyle's harassment lawsuit against Romano, but Kerry gets Romano to rewrite his insulting and inaccurate review of Doyle's job performance. The ER unites to help an injured woman who needs to find temporary homes for her many dogs as she gets treatment. Mark treats the hospital janitor, Mobalage, whose injuries suggest he has been tortured in the past. Carter discovers something with one of the med students he is mentoring.

Doug faces possible criminal charges after Ricky Abbott dies when Ross shows Joi how to give Ricky a lethal dosage of medication. Doug is delegated to desk duty, Carol's clinic is shut down for acquiring the P.C.A. machine for Ricky, and Greene and Weaver face future disciplinary action for not reporting Doug's earlier mistakes. Meanwhile, Carter and Lucy discover a mutual attraction, Benton studies with a sign language instructor, and Romano begins his first day as acting ER chief.

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.

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.

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.

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.

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.

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.

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

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.

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.

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.

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.

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.

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. 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.

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

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.

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.

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.