Dr. Pratt and his passengers -- Dr. Chen and Elgin -- try to elude gunfire from another motorist until Pratt loses control of his sports car and crashes into the Chicago River -- trapping them underwater as rescue crews troll overhead. When recovered, all three are hospitalized with serious injuries that soon spiral downward. Elsewhere, Nurse Sam seeks to escape her returning boyfriend and hits the road to find a new life with her son Alex just as Neela makes a surprising entrance in the E.R. In addition, a somber Dr. Carter and Kem deal with their unborn son's remains, Dr. Weaver intercedes when a cop wants to perform a pelvic exam on a young woman who's hiding a stash of marijuana in a private body part -- and two new interns make an immediate impact.

A lonely Dr. Carter struggles with his unfulfilled dreams in the wake of his girlfriend Kem's departure -- and lurches toward a dangerous temporary solution -- while new doctor Abby faces resentful nurses and tends to a tearful and injured young woman kidnapped from Mexico and forced into sexual slavery. Elsewhere, Dr. Kovac makes an honest confession to a fleeing Sam while Neela must face the music when her domineering, old-school Indian parents arrive in a huff after she abandoned her Michigan medical assignment. In the meantime, Carter treats an Iraqi war veteran who was disfigured in combat, Dr. Weaver suggests to new intern Ray that he tone down his alternative-punk look in deference to frightened patients -- and two ER staffers recover from their injuries.

It's a busy 4th of July weekend and Carter tries to run an understaffed hospital, which is flooded with patients. A biker with HIV is left brain dead from a robbery and his girlfriend wants to donate his organs to a fellow friend, who is also infected with HIV. Carter persuades Corday to perform the organ transplant after several surgeons refused to perform the operation. Meanwhile, Ray is upset with Abby for going above him and ordering a drug test on his patient, a bicycle messenger. Abby later asks Carter out for dinner and drinks in hopes of talking to him about his past problems. Dr. Pratt is back early from his recent craniotomy and is not operating at his best capacity. Carter notices his insensitivity to a stabbing victim as well as the fact that he is still suffering from headaches and sends him home. Corday confronts Weaver on her latest surgeon choice and the fact that she was not involved in the decision-making process. Lastly, Neela looks for employment outside of the medical field and has a hard time finding a decent job.

Two small children are rushed to the ER after falling from a third story window. The attending staff believes an abusive father is at fault for the tragedy but not all is as it seems initially. Pratt treats a man who believes he has an unsightly rash which turns out to be lung cancer. Dr. Corday is disciplined by the hospital for performing an HIV+ organ transplant; instead of dismissing her, they offer her a non-tenure track position. Sam contemplates moving in with Kovac. Neela decides to leave her job at the mini-mart after Lewis, the new Chief of Emergency Medicine, offers her a job at the hospital.

Neela returns to the ER after working at the Convenient Store near the hospital. On Neela's first day, Pratt expects the interns, Abby, Ray and Neela to take on a large patient load during their shifts at the hospital. Pratt turns processing the patients into a competition, in which Ray is clearly going to be the winner. In the rush to process the patients and stay in the lead, however, Ray makes a big mistake donating a patient's organs against the family's wishes. Ray helps Abby obtain HIV medication from the pharmacy against hospital policy for a patient that had unprotected sex. Carter asks Wendall to walk out with him in a coy pursuit.

In a ground-breaking episode which traces the real-time events in the emergency room, Kovac, Abby and Sam try to save the life of Charlie Metcalf, a man who comes in complaining of a stomach ache, but is later diagnosed with far, far worse.

Sam and Kovac treat a woman who was brutally beaten and raped and wants to help police although she can barely speak. Lewis schedules a JCAHO emergency drill without telling the staff. Carter and Abby treat a girl complaining of kidney problems, which is just the beginning of her adventure.

When a police officer shot during a robbery is brought to the ER, Lewis, Neela and Ray stabilize him, but the injuries to his carotid artery leave him in a coma. His fifteen-year-old son must decide whether to authorize a risky operation which may save his life or leave him in the coma. Abby tries to convince a girl with appendicitis to have surgery at County General, but her father wants her transferred to Mercy because his father died during surgery at General.

It’s Christmas Eve, and the ER staff scrambles to leave for the holiday. Abby receives a dialysis patient who is in critical condition, but she can’t reach his physician because he doesn’t want to be disturbed during the holidays. After much effort a distraught Chen finally finds someone to cover her shift so she can attend to her ailing father. Concerned for her, Pratt stops by her house to find her struggling with her father’s worsening health. Carter and Wendall grow closer and share an awkward kiss as they wish each other a Merry Christmas.

As Abby smokes in the ambulance bay, an SUV pulls in carrying a gunshot victim. When Abby runs to the car to help the patient, she's pulled inside at gunpoint and driven away. Ray begins treatment on a woman who soon requests a new doctor. At first Ray is offended, but then learns that there is more to the patient's story than meets the eye.

Lewis assigns Kovac to teach the residents how to communicate more effectively with their patients in hopes of raising their patient satisfaction scores, which have plummeted. They are put to the test when two teenagers are brought to the ER with gun shot wounds. Kovac, Neela and Sam handle one patient while Lewis, Pratt and Ray deal with another. When a patient dies, Neela does a poor job of informing the deceased's grandmother, who becomes hysterical in the middle of the ER. A personal injury lawyer sets up a mobile office outside the ER, infuriating Lewis as he tries to turn dissatisfied patients into clients. Abby returns to the ER, still dealing with the trauma of her abduction.

When a sixteen-year-old girl who had received a kidney transplant from her father arrives at the ER feeling dizzy, Carter traces the problem to a new drug called Zarictal that the girl was taking to control seizures related to her kidney dysfunction. Her father feels guilty because he was the one who pushed for her to take the new drug and its side effects may mean his daughter will have to go back on dialysis. Carter asks Neela to post questions about the drug's side effects on the internet, which causes an uproar when the pharmaceutical company finds out. After Abby and Neela complain about their lackluster dating lives, they end up assigned to work with Jake and Kovac whom they each seem to have a crush on.

While examining a young boy, Pratt finds a suspicious gash across his chest and calls Wendall for a consult. Kovac and Pratt examine a man who got shot when he confronted his boss with a gun. Jake tries to convince Abby that being a student shouldn't keep him from dating her.

Dr. Weaver encounters an evasive patient who shocks her by revealing that she is her birth mother, who put her baby up for adoption at 15. As they spend time sharing their life stories, their budding relationship withers when Weaver confesses to her mother -- an evangelical Christian -- that she is gay. Elsewhere, Dr. Pratt warily turns over an addled elderly woman to the care of Jane while Dr. Carter causes a commotion when he confronts a couple hoping to scam some painkilling drugs.

When a young mother of three is brought into the ER with potentially fatal stroke-like symptoms, Kovac and Sam race against the odds to save her life. Knowing that a controversial surgical procedure is his wife's only shot at a full recovery, a husband must make the unenviable decision to risk her life in order to save it. Meanwhile, Neela and Ray discover a dark secret when three ostensibly neglected children show up in the ER. Elsewhere, Carter finds himself in the midst of a love triangle when Wendall's professions of love force him to either cut the ties in Africa or lose her.

A young girl in Iraq is wounded in a car bombing and local hospitals are unequipped to help. Gallant enlists the support of Neela to secure the needed treatment at County, but getting the girl to the United States proves to be more difficult than initially thought. With time running out, Gallant must resort to calling in a favor to bring the young girl to the states. Meanwhile, Neela is redefining her role at County and rediscovering her feelings for Gallant.

Neela is surprised when she hears that Gallant came to the ER with the young Iraqi burn victim. Sam is troubled by a visit from her ex-husband. Pratt treats a child whose gun went off in his pocket and learns that he received the gun from an unusual source.

A woman is brought in suffering from the effects of a hunger strike, but she will not accept food or help until she has proof that the INS will grant her son’s deportation case a new hearing. Neela, Sam, and Dr. Lewis are incapable of treating her as long as she and her lawyer refuse aid -- which goes against all the doctors’ training. Meanwhile, Abby, despite her suspicions, is unable to prove that 72-year-old Birdy Chaddock is the victim of elder abuse.

85-year-old Jules Rubadoux is wheeled in and erroneously accuses Dr. Carter of killing his wife ten years ago. Although Abby believes Rubadoux is too old to undertake surgery to correct a heart murmur, the attending doctors opt to go ahead with the operation. Meanwhile, Dr. Pratt treats a domestic violence victim and makes a date with the social worker assigned to her case. As Pratt arrives for the date he realizes he has gotten himself into more than he bargained for.

Dr. Morris has been appointed the new chief resident and immediately locks horns with Dr. Pratt as they deal with the casualties from a fire at an apartment building. Dr. Lewis is taking out her frustration from not being tenured on Dr. Carter. Dr. Weaver tries to calm Lewis down, but only makes things worse. Ray heeds the advice of several doctors at the hospital and sends a teenaged sickle cell anemic patient home.

Pratt explodes at Neela for performing a complicated procedure on a baby, Abby misdiagnoses an emphysema patient, and Ray's procedural misstep on a stab victim has terrible results. Outside of the ER, Carter dashes off to Paris after learning that Kem's mother has been hospitalized. Once there, Carter discovers some things about himself and makes some life-altering decisions.

On Carter’s last shift, four new interns begin their tour of duty. After completing their rounds, Carter, Kovac and most of the ER staff head out to Carter’s surprise going-away party down the street at Ike’s. Ray leaves to go to another party where the revelry is interrupted by a disaster which truly tests his mettle. The casualties are taken immediately to County General where a skeleton staff headed by Abby and Neela must step up to the plate all on their own. Elsewhere, Pratt finally gets the courage to confront his father Charlie. Sam and Kovac search for Sam’s son after he runs away in search of his imprisoned father.