When an STD breaks out, affecting several members of the staff, Webber calls a staff meeting. Later, the chief confides in Derek about his own medical concerns. Izzie and Cristina become stressed when a patient's wife and daughter can't decide on his care. Burke treats an old college friend, Bill, but his diagnosis creates questions about his wife. As Meredith and Derek continue to get closer, their relationship crashes down around them when a person from Derek's past shows up in his life.