J.D.'s older brother Dan (Tom Cavanagh) drops by for a visit, but J.D. can't hide how ashamed he is of his brother's life. Turk learns a lesson when he makes a bet with Dr. Cox on whether a patient lives or dies. Meanwhile, Sacred Heart staff is in costume for Halloween, and one person in particular is wreaking havoc in a gorilla suit, much to Dr. Kelso's disgust.