The pilot for the popular TV series is set during 24 frantic hours in the lives of a group of doctors, nurses, and staff members of a busy emergency room at a Chicago hospital. They deal with the seemingly endless casualties that stumble into their place of employment. The central characters are the chief resident and family man Dr. Mark Greene, who is considering a job in private practice due to pressure from his demanding law student wife Jennifer; outgoing Dr. Doug Ross, who deals with cases in his own personal way; straight-arrow Dr. Susan Lewis, trying to get by another long 36-hour shift; inexperienced third-year med student John Carter; cocky surgical resident Dr. Peter Benton; and troubled chief nurse Carol Hathaway.

Mark's wife arrives in the ER with the news that she has passed her bar exams but several members of the staff interrupt their intimate celebration. Greene treats an elderly woman whose husband isn't ready to let her go. It's been eight weeks since Hathaway's attempted suicide, but Doug Ross has yet to bring himself to visit the woman he went out with for two years. Susan Lewis saves a newborn who is brought into the ER choking. She also argues with the psychiatric attending who refuses to admit a patient suffering from dementia. Carter finds himself having to care for a group of German tourists who are suffering from food poisoning. He also treats a young flirt with a rash. Benton treats a recent surgery patient and finds his correct diagnosis overturned by the man's physician. Susan Lewis treats a family struck by a drunk driver. The husband and daughter will survive but there is little hope for the woman. The drunk driver is also brought in suffering from only a few scratches.

Carol Hathaway returns to work after her suicide attempt. Doug Ross still feels guilty about what happened. An ER patient found walking the streets takes to singing, constantly. Susan Lewis has a run-in with the cardiologist on duty, Dr. Kayson, when he disagrees with her treatment of a heart attack victim. At a case review session, she gets very little support from her colleagues. She also treats a woman who is dying of leukemia and who has good advice for Hathaway. Greene treats a woman who has obviously been beaten by her husband but can't get to agree to get help.

Drs. Benton and Langworthy are unsuccessful in reviving a teen-aged boy involved in a traffic accident and it's left to Carter to determine the boy's identity and notify the parents. Unfortunately, he tells the wrong parents that their son is dead. Doug Ross tells a young patient that he will not be separated from his schizophrenic mother knowing that she will likely be hospitalized for a long time. Susan Lewis tells Mark that she is dating the psychiatric attending physician Div Cvetic. She also treats a salesman whose cell phone is having an odd effect on hospital equipment. Benton forgets that he was supposed to sit with his mother while his sister and brother-in-law were to go out for their tenth anniversary dinner.

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.

Doug Ross' hopes of renewing his relationship with Carol Hathaway take a positive turn after the two of them kiss following a particularly stressful trauma, but his hopes are dashed when she decides to move in with boyfriend Tag. John Carter has a particularly good day when Dr. Green successfully walks him through a complex procedure. Haleh takes Dr. Benton to task when he refuses to act as a role model for a young gangbanger she has an interest in. Benton is also competing with Dr. Langworthy for a prestigious fellowship. It's Susan Lewis' birthday and her sister Chloe shows up at the ER drunk.

Susan Lewis' boyfriend Div Cvetic, a psychiatric resident at County General, seems to be under a great deal of stress regularly lashing out at everyone. Doug Ross takes over for Mark Greene who takes a day off to be with his wife. He has a hard time keeping up with all the paperwork. John Carter is increasingly frustrated with Peter Benton who never seems to invite him to participate in surgeries. Benton learns the result of the fellowship he applied for and his mother shows up in the ER with a sprained ankle. Carol Hathaway treats a patient who was raped. A new ER aide, Bob, start work.

Carol Hathaway faces an ethical dilemma when a patient admits that he, and not his friend, was driving the car that ran a red light and killed a pedestrian. She decides to tell Tag about kissing Doug Ross. It's Thanksgiving and the doctors treat an animal rights activist who was attacked by the turkey he was trying to save. Doug Ross is going to the Bahamas with Linda Farrell and he is very much feeling like a kept man. Carter has to treat a transgender woman who has now reached an age where she can no longer pass as a woman. Carter's indifference is the final straw. Susan Lewis continues to worry about Div Cvetic, whose condition seems to be worsening.

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

It's Christmas-time and the expected range of emotions is to be found among the ER staffers. Susan Lewis treats a middle-aged woman who is overjoyed at finally getting pregnant. Susan is also shocked to hear that her boyfriend Div Cvetic has quit his job and moved out of his apartment. Mark Greene treats a young drowning victim. Doug Ross takes Greene's advice and decides to tell Carol Hathaway that he loves her; unfortunately he chooses to do so at her engagement party. Peter Benton jumps the gun and arranges for transplant teams to harvest an accident victims organs but the man's wife is now refusing to give consent. Susan's sister Chloe announces that she is pregnant.

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.

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.

Carol Hathaway goes ahead with her plans to adopt Tatiana, but her past history makes her ineligible. Benton continues to trade shifts so he can spend time with his mother but it all catches up with him and he has a run-in with Dr. Hicks. Doug Ross treats an abused child. Green, Benton and Carter take extraordinary measures to save a man they later learned had signed a DNR. A consultant arrives to study procedures in the ER, but all is not quite what it seems. Mark Green's wife Jen has an important announcement. Benton's mother has a serious accident when he falls asleep on the couch.

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.

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.

Doug Ross and Nurse Hathaway treat a girls' basketball team from a local catholic school for meningitis. Their teachers also need to be tested but one of them confides in Hathaway that she may have a particular problem. Green and the Chief of Staff have a disagreement in the middle of a procedure. With the wedding only two weeks away, Tag and Carol Hathaway have to deal with all of the final preparations, not the least of which is writing their own marriage vows. Susan deals with a suicide victim who is using emotional blackmail to keep his girlfriend from leaving him. Susan reaches the breaking point with her sister Chloe and tells her she has to move out.

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 saves a kid who's stuck in a flooded culvert and becomes a local hero when a TV helicopter films part of the rescue operation.

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.

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

Benton has to attend a banquet at Vucelich's home and asks Jeanie to go with him. Mark hesitates to tell Rachel about the divorce.

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

Benton tries to save someone who, according to the other surgeons, can't be saved while the ER gets crammed with pregnant women.

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

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.

Doug's one-night-stand has a seizure and he brings her to the ER.

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.

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

Benton can't keep his mind on the job, Mark and Chuny break up and Carol does what she needs to do regarding the fatal error she has made.

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

Carol will hear whether her suspension is permanent or not. Mark and Doyle do what they can to get a patient with Down syndrome on a heart transplant list.

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.

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

Anspaugh is furious when Carter tells him he wants to quit surgery. Charlie is brought in with an overdose. Mark keeps struggling with his beating.

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.

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.

Carol would like to have a women's and children's health care clinic within the ER. Benton has trouble combining work and fatherhood.

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

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.

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

When a compatible bone marrow donor cannot be located, Scott Anspaugh agrees to undergo a new round of chemotherapy, even though there appears to be little point. Doug Ross suggests to Jeanie Boulet that Scott may have agreed to the therapy because of her. Mark Greene has taken on the task of organizing the annual ER banquet only to find that Jerry, on whom he had been relying for much of the preparation, hasn't quite delivered. John Carter confronts his grandmother when he learns that she has cut off funding for Carol Hathaway's free clinic. In the OR, Peter Benton has a major confrontation with Dr. Morgenstern, pushing him aside and taking over an operation. Greene and Weaver criticize Doug Ross over his handling of a sick child and her mother.

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.

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.

Carter and Weaver become unlikely roommates. Lucy is having problems with Carter, and Greene picks up on their squabbling. Corday works long shifts which leads to her exhaustion and a critical medical error, causing a rift with Dr. Anspaugh and problems for Benton. Greene has unpleasant flashbacks when he's hazed by the well-meaning paramedics. Jeanie worries when she and Doug treat a young boy whose childlike mother clearly depends on his 6-year sister to make all decisions. Kerry rediscovers her joy of practicing medicine and decides not to pursue the open ER Chief job, which goes instead to a Dr. Amanda Lee.

A man arrives at the ER with his gravely-injured daughter then runs out, presenting a critical situation because he's the only match for her blood type. While Carter and Lucy alternately bicker and work well together as they try to track down the father, blood-supply snafus spur Benton to perform an unprecedented operation on the girl.

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.

It's Christmas day in the ER. An 18-year-old boy arrives brain-dead, and Carter has to convince his parents to donate his organs, since a 16-year-old girl needs a liver. Benton risks his career by preventing Romano from operating under the influence. Ross and Hathaway have a religious dispute over how to deal with a pregnant 13-year-old. Corday is charmed by a musician who is facing surgery for prostate cancer. Dr. Lee flirts with Mark but turns out to have some major issues and strange story-telling habits.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Benton tries to save someone who, according to the other surgeons, can't be saved while the ER gets crammed with pregnant women.