On Michael's first day as Chief of Internal Medicine, Joan arrives at the hospital as a patient in dire straits. Amy, determined to save her, clashes repeatedly with Richard over Joan's treatment plan. Meanwhile, Gina makes a nearly impossible medical decision for a young patient and Liz fights for her allegations against Richard to be taken seriously.

In an effort to save a crashing Richard from a deadly virus, Amy gets infected with it. Michael and the team work tirelessly to help her and the other patients, but their experimental treatments fail, and Amy becomes critically ill.