Lewis treats an end-stage Huntington's patient, whose mother has already watched her husband wither from the disease. Abby's brother Eric, an Air Force traffic controller, visits on his way to a new post in Nebraska. Carter tends to a 12-year-old drug-addicted prostitute with a serious STD, until her pimp shows up and whisks her away. Pratt aggravates a drug-seeking man who comes back brandishing a gun at Chen and Abby and demanding Demerol. Abby gives him his shot but purposefully ODs him. In the aftermath, Carter flips his lid, demanding better security and the installation of metal detectors. When Weaver refuses, Carter leads a walkout. Weaver eventually caves, albeit before telling Carter that he must fire three senior nurses by the next morning to make up the expense. Abby, Lewis and Chen go to a concert to decompress.

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. In a moment of personal weakness, he tries to express his feelings for Corday. Weaver continues to display erratic behavior, raising staff suspicions about her menopause. Luka's burgeoning sex addiction worsens, as an affair with Chuny is revealed, and tensions rise when he treats a patient with a perpetual erection.