Billy Callahan is a life-loving Irishman who comes to Sacred Heart Hospital after being injured in a bar fight and teaches Turk and J.D. a lesson about living life to its fullest. Meanwhile, Carla and Elliot attempt to make social plans with each other but can't seem to stick with them, which creates tension between the two friends. Elsewhere, Dr. Cox gets a vasectomy behind Jordan's back and is stunned by her reaction when she discovers the truth.