Carla's brother Marco visits and does his best to aggravate Turk. Dr. Cox and Dr. Kelso differ in their opinions over patient care, and Dr. Cox is surprised to find that J.D. is taking Dr. Kelso's advice. J.D. is interested in Danni, a girl who seems sweet, if a little wacky (she has an active inner monologue and speaks random thoughts aloud). But his delight is squashed when he discovers she's Jordan's sister.