A severe blizzard leaves the ER utterly devoid of patients, leaving the staff free to goof off. In the middle of their fun, a call comes from dispatch, informing the ER of a 40-car pile-up with dozens of casualties. The ER goes from being deserted to capacity. All surgeons are called in. Bob surprises everyone with a quick and life-saving decision. A new doctor, Angela Hicks, arrives just at the right time. Ross and Linda return from the Caribbean just as Carol makes a surprise announcement.

Carter fumbles his way through his first look at surgery. Dr. Lewis' nemesis, Dr. Kayson, makes her New Year's Day decidedly unpleasant. Chloe announces she's moving to Texas with her boyfriend.

A case of apparent spousal abuse is not what it seems. Deb outshines Carter after he is up all night preparing for a presentation. Peter informs Jackie he's hired a helper for his mother. First Kayson's reprimand against Susan is denied, then Susan has a chance to prove herself when Kayson is brought in as a patient. Dr. Ross meets Diane Leeds, of risk management, and her son Jake.

Morganstern invites Mark to join the staff as an attending physician. Mark treats an woman with breast cancer, who begs him to kill her. Deb "wows" Benton with her amazing presentation, leaving Carter in the rear again. Benton offends Haleh, who spends her day making his job extremely more difficult. The ER gets new crash carts, which are promptly stolen by cardiology.

Dr. Hicks berates Benton when he tries to switch shifts to attend his mother's birthday party. A teenage girl, a frequent patient of the ER, is brought in for a drug overdose. Carol decides she wants to adopt Tatiana while Tag isn't so sure. Dr. Ross slugs an abusive father in the lobby. Jen accepts a job offer in Milwaukee despite Mark's offer from Morganstern. Deb and Carter await the arrival of sub-internship applications.

A busy Dr. Greene goes all day in solving his patients' problems until he encounters the case of a pregnant woman suffering from complications that threaten both her life and her unborn baby's.

Deb and Carter compete furiously for procedures after Benton announces their books are due a week earlier than previously announced. Deb commits a nearly deadly error on a patient while trying to keep up with Carter. Doug's relationship with Diane Leeds grows. Peter and Jackie decide to put their mother in a home. Dr. Greene is put on trial, so to speak, in the M conference for Jodi O'Brien. Chloe returns.

Susan is forced into the role of parent when Chloe gives birth and both Chloe and her mother, Cookie, shirk responsibility. Doug is surprised and a bit frightened when Diane suggests they move in together. Unfortunately, Linda Farrell happens to be around to take advantage of his nervousness. Carter is offered the ER sub-I but turns it down in anticipation of receiving a surgical position. Peter receives unpleasant news; his mother has died.

Weaver and Susan's feud escalates to the point where Mark needs to step in and fix it. Benton is involved in a parking lot altercation, resulting in a broken hand and Carter replacing him in surgery. Mark cares for an abandoned elderly woman. Susan tries to juggle her work and care for Little Susie. Shep risks his life to bring in a gunshot victim.

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.

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

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

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.

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.

A 31-year-old security guard is brought in suffering from severe chemical burns, and a 21-year-old man is wheeled in after falling 75 feet into a river. Meanwhile, Benton is upset that Carla's boyfriend is part of Reese's baptism.

Dr. Corday commits a deadly error after being on-call for nearly 36 hours straight. Peter visits Dr. Kotlowitz and receives encouragement regarding a cochlear implant for Reese. Dr. Amanda Lee, a prospective new ER chief, visits. In the wake of a failed pregnancy attempt, Carol lashes out at a mother using abortion as a means of selective birth control. Carter and Lucy feud when Carter accidentally uses her palm computer and finds out what she thinks of him. Mark panics during a paramedic initation.

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.

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.

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.

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.

Corday rushes through a surgical procedure in order to take off on a romantic weekend with Greene. She is later called back to the hospital after her patient suffers complications. Abby's mother, Maggie, who suffers from bipolar disorder (manic-depressive) and refuses to take her medication, unexpectedly visits Abby at the hospital and wreaks havoc on Abby's life.

Tests reveal that Greene has a brain tumor, but he hides the news from Corday. Corday finds out that she is being sued for malpractice. She also reveals to Greene that she is pregnant. Abby's mother refuses to leave. Abby expresses resentment over her difficult childhood to her mother but resignedly brings her home for Thanksgiving dinner.

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

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

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

A new medical student, Michael Gallant, arrives in the ER. He's supposed to be working under Dr. Carter's supervision but his grandmother is unwell. Elizabeth Corday is convinced that other doctors are refusing to work with as a result of the mysterious deaths.

Peter Benton continues his court fight against Reese's stepfather, Roger, who seems to have the upper hand. When a woman is accidentally shot during a gas station robbery, Dr. Corday tries to convince the husband to let them harvest her organs. A 15 year old boxer is brought in with a head trauma after sparring with his older brother. Newlyweds are having trouble when she constantly breaks out in a rash; Carter thinks he knows the cause.

Benton commits perjury on the witness stand in order to gain custody of Reese. When Romano refuses to give him a more even schedule, Peter resigns and seeks a job at the clinic where Cleo is newly employed. Benton is granted custody of Reese and he and Cleo decide to move to the suburbs together. Meanwhile, Carter's father visits for Christmas with the news that he's getting divorced, Weaver and Sandy Lopez finally go on a date, and Abby catches Nicole in the maternity ward, recovering from an abortion.