Greene fears the outcome of a board inquiry into the serial killer he treated. Carter goes to a familial burial and has to deal with his aloof parents. Benton tends to both Cleo and his sister. Weaver comes back to the ER after some time away.
Dr. Carter tries to leave at the end of his shift, only to be swamped with problematic patients, including several heavy-metal roadies involved in a concert accident. Newly appointed chief resident Chen is overwhelmed with patients and Dr. Weaver is nowhere to be found. Unable to consult with Weaver, she misdiagnoses one of the patients and the patient dies. Meanwhile, Abby and Dr. Kovac are out on the date from hell.
Greene is shocked when his daughter runs away from his ex and comes to him in the ER. Carter and Abby grow closer. Chen works to save an infant with an odd birthmark. Malucci tends to a person trapped in an elevator with him. Romano and Weaver butt heads over a newspaper investigation of an ER death.
Lewis comes back to Chicago looking to pick her life back up. Chen and Weaver are walked through the details of the death of one of Chen's charges. Benton juggles a difficult surgery and the knowledge that he has to pick up Reese from school. A French woman seeks out Kovac.
Lewis tries to regain her footing at Country General. Greene tends to a man accidentally struck down by his daughter's car. Benton receives news that his son has disappeared. Corday faces drama at home and at work when Greene's daughter moves in and Corday has another patient die under her care.
With multiple patients dying under her watch from infection, Corday is followed around by a watchful eye on her cleanliness. Lewis tries to save college students from a deadly virus. Benton and Roger go head-to-head over Reese visitation. Kovac convinces his superiors on a risky hire. Greene tries to keep the two women in his life, his wife and daughter, from each other's throats.
Corday seeks out the person really responsible for her patients' deaths. Benton agrees to a paternity test to prove his blood-tie to Reese. Lewis and Carter try to deal with a self-mutilating girl. Abby comforts Nicole, even though she still has hard feelings over Kovac. Gallant joins the staff of the ER.
A hard rainstorm hits Chicago and floods the E. R. with injured people.
Benton fights Roger for custody of Reese. Corday waits on a husband's decision to donate his terminally ill wife's organs. Greene and Lewis treat a young brain damaged teen for boxing injuries. Rachel's boyfriend tests positive for marijuana use.
Benton fights Romano over a schedule that would free him up to take care of Reese, fails and decides to leave the ER. Weaver wonders about a child's origin when a comatose patient comes to term. Abby finds Nicole sneaking through the ER. Carter handles his father's Christmas visit.
Abby tries to keep Carter away from the person who stabbed him and killed Lucy Knight when the man checks into the ER. Carter fights with his mother over family problems. Abby receives the odd word from both Kovac and her ex-husband. Chen meets with Carter over evidence used in her dismissal.
A condemned murderer is brought into the ER. He asks to die in the ER rather than await execution. Abby tries to help her neighbor get away from her abusive husband.
Dr. Greene and Dr. Corday's baby accidentally swallows an XTC pill left out by Dr. Greene's troubled teen daughter. Abby helps her female next-door-neighbor hide from her abusive husband.
Dr. Corday orders Rachel to leave her home, sparking an argument with Dr. Greene. Abby continues to try to protect her battered neighbor who refuses to press charges against her husband.
Dr. Greene hides from his loneliness by burrying himself in his work. Chen learns that a comatose teenage patient is pregnant.
The staff go to a sexual-harassment session after a couple of the doctors are caught rummaging through a dominatrix's left behind tools. When true feelings are revealed, Susan breaks off her relationship with Carter.
The ER is flooded with victims from a fire, among them is a dear friend of Weaver's. Corday and Greene have an awkward encounter in the ER.
Greene grows concerned when his illness starts to affect his muscle coordination and he sees the path ahead of him played out in his patients. Greene consults Pratt on how to handle patients.
Lewis rushes off to New York City when she gets a frightened message from her niece. Helping her there are Officers Yokas and Bosco (from "Third Watch"). Pratt defies authority and convention in trying to save a dying patient. Carter confronts Kovac over Abby's return to alcohol. Weaver tries to help a couple with a brain-dead son and their decision as to whether to continue his use of life support.
Greene writes a letter to the ER staff which Carter reads. Greene receives another visit from a terminally ill homeless man. Weaver explodes at a mentally challenged patient.
Greene spends his last days at his childhood home in Hawaii with his difficult daughter Rachel trying to patch things up between the two of them and offer to her what wisdom he's accumulated during his life.
When two children show signs of illness, the ER is placed into quarantine. A riot breaks out in an attempt by some frustrated people to get out of the hospital. Pratt and Chen put aside the fear that they may have caught the disease in order to save the life of Stan the Can.