Turk saves a man's life at the taco stand, but Cox taks the credit; Elliot enlists J.D.'s help to prevent her dates with Jake from becoming too intimate; Kelso terrorizes the hospital from his motorized wheelchair.
Jake (Josh Randall) brings in his dying neighbor and helps convince her it's time to die, but gets sued by her brother; Elliot goes to Cox and Carla for romantic advice with Jake; Turk has problems in couples therapy.
Molly returns to Sacred Heart and J.D. blows off Kylie to go out with her; Carla finds out Turk is still in contact with his ex-girlfriend; The Janitor bets Cox his van for Cox's porsche he can get a date with Elliot.
J.D. and Cox have to deal with a manipulative malpractice lawyer, Neena Broderick (Julianna Margulies); Turk tries to avoid a hypochondriac patient Harvery (Richard Kind); Elliot steers Doug on a new path.
Dan (Tom Cavanagh) comes to visit J.D. to tell him their father died; Cox has problems helping J.D. cope; Turk has symptoms of diabetes but refuses to go to a doctor and Molly uses psychology to convince him.
Turk and Carla begin to have issues as she attempts to change her new husband; Molly (Heather Graham), a new psychiatrist becomes friends with Elliot; Carla lets Turk pick out a new car but instead he buys three scooters.
J.D.: Hey, I heard a great joke. A guy walks into a dentist's office and says, "I think I'm a moth." And the dentist says, "Well, if you think you're a moth, why are you at a dentist's office?" J.D.'s narration: Oh, no, I forgot the punchline... You can't bail out now! Stall! Stall! J.D.: ...So the moth says "That's a good question. What kind of dentist are you?" And the dentist says, "Well, I'm a general dentist, but I...I do dabble in orthodontry - braces and such." And... and the moth says, "Orthodontry? I hear there's great money in that." J.D.'s narration: "The light was on"! J.D.: "But! To answer your original question, which was, if I think I'm a moth, why am I in a dentist's office? The answer is, Because the light was on!" The light! The light, James. Moths love light. So, James, other than your funny bone being broken, what seems to be the problem?