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.