Dr. Carter, Abby and other staff of the ER are quarantined as the CDC investigate a mysterious, deadly outbreak
After another hospital shuts down, the ER is flooded with patients. Dr. Pratt resuscitates a heart-attack victim who had been pronounced dead
Dr. Carter leads a walk-out of staff protesting lack of security in the ER
Weaver makes a mistake on live television while demonstrating flu shots, inadvertently sticking two reporters with the same needle. In the bathroom later, Susan and Abby catch Weaver in a stall with a needle. Weaver confesses to Susan that she's taking hormones
On a busy Halloween night, Carter and Abby are the only staffers in costume when victims of an apartment building fire pack the ER. Corday takes on a new med student for a surgical rotation - Paul Nathan, who suffers from Parkinson's disease and decided to pursue medicine after being diagnosed. Despite a difficult first day, both professionally and medically, Nathan makes a difficult diagnosis
Corday clashes with new surgical resident Paul Nathan regarding his intervention into the treatment of a sickly young woman, Alison, who has signed a "do not resuscitate" order. Abby wonders about the erratic behavior of her visiting brother Eric, and feels conflicted over a nurse's official complaint against Kovac, Abby's former lover. Meanwhile, Pratt comforts Chen after a patient threatens her, and Corday suspects that an unconscious, 14-year-old female patient has been sexually assaulted
Abby fears the worst when her brother Eric suddenly disappears. Carter and Chen treat a frightened Chinese immigrant nanny, Tong-Yi, whom they suspect was impregnated by her employer. Meanwhile, new surgical resident Paul Nathan, who is struggling to overcome a physical disability, tries to help in the emergency room—but his fellow doctors do not appreciate his advice to patients
Abby's family nightmare continues as she and her mother Maggie search for Abby's missing brother Eric, who Abby suspects is suffering from serious mental problems. Meanwhile, Corday treats a family of patients who, while building a snowman, were severely injured after being struck by a truck driver
Abby is distressed when her mother interferes with Eric's treatment at a psychiatric hospital. Pratt treats a frightened young girl who has been injured in an auto accident and desperately wants to hide a secret. An unhappy Luka forms an unlikely bond with a lonely elderly woman who makes him a surprising offer
Dr. Kovac's speeding causes a crash on an icy road. The ER staff treats angry elves and a female hockey player with a head injury
Dr. Pratt brings a gun into the ER; Dr. Weaver tries to conceal her pregnancy; a woman plots against her dying husband; Dr
Dr. Weaver is in a difficult situation when an alderman tests positive for syphilis. Dr
Dr. Pratt's disabled roommate leads him to a wounded thief. Dr Carter decides to practice medicine in Africa
Abby's troubled brother is missing. A car runs into a crowd of teen girls. The alderman with syphilis gives Dr
Abby comes close to breaking down trying to deal with her mother. Dr. Pratt goes for his required paramedic ride-along
The police question Drs. Pratt and Gallant about a rampage at the diner across from the ER. Dr
Dr. Weaver bends the rules and treats the Alderman's lover for syphilis. Dr
Dr. Romano seizes control of the ER and manages to offend everyone. Dr
A psychotic patient threatens Abby. Dr. Weaver suspects a woman poisoned her own baby
Dr. Carter tries to prevent a grieving gang member from going after vengeance. Dr
Carter's day shift and Pratt's night shift (his final shift at County) are intercut. Both men have extremely busy days. Doc Magoo's burns down
Carter travels to the Congo after Luka calls and asks for help. During the course of his two weeks there, he learns how much different the conditions are against what he's used to. Luka decides to stay for a while as Carter heads back to Chicago, ending up at a sleeping Abby's bedside