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.

Abby fears the worst when her brother Eric suddenly disappears. He is actually AWOL and she forges Carter's name to obtain his medical records. 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. Unable to quench his sexual appetites, Kovac also gets into trouble in his professional life, despite his admirable resolve to find an eye specialist to treat a young gunshot victim. Gallant and fellow medical student Erin Harkins engage in an escalating competition of medical knowledge. And Weaver gets some much-needed good news.