Derek and Meredith try to be discreet as they spend the night together at Meredith's house, but their haggard appearance speaks volumes to Bailey, who warns Meredith to end the relationship. Meanwhile, George suspects an anesthesiologist of drinking on the job, Alex treats a former competitor who now finds honor in self-mutilation, Izzie has to deal with a patient who won't let his girlfriend go, literally, and Cristina battles a case of what seems to be the flu.