ER

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. Carter, assuming Susan knows already, tells her about Abby's drinking problem. Abby becomes nurse manager, and argues with Carter about her drinking. Luka flirts with a patient's mom and is caught emerging from a storage closet with her. Gallant has a rough day: Pratt butts in on a patient of his, and Stella Willis dies because Kayson didn't bother with thorough treatment.

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. Romano's rehab lags behind his expectations, and he begins to doubt his role in surgery is no longer an option.

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.