Elliot's wild sorority sister, Melody comes to town. Not able to deal with being the fifth wheel, J.D. turns the girls against each other in the hopes that he will once again be Elliot's priority friend and he might get to "mack" it with Melody. Meanwhile, Turk and Dr. Cox go head to head when they disagree over whether or not a patient requested surgery is necessary. Elsewhere, Carla discovers an unlikely ghost haunting pediatrics in an attempt to keep it clean.