It's time for the annual 4077th Halloween party. Hawkeye is dressed as Superman, B.J. is a clown, Margaret is a geisha girl, Colonel Potter is a cowboy and Klinger is Al Capone. But it's not much of a party for the surgeons when unexpected wounded guests show up; Charles tries to help a slovenly marine who has a billiard ball stuck in his mouth; Father Mulcahy inadvertently saves a man's life when he is presumed dead.

It's another M*A*S*H prankathon. This time, Hawkeye appears to be the marked man after menial practical jokes happen to everyone in camp, but him. Will they get him too? Or is Hawkeye already the victim of an even larger practical joke?