All the nurses have been evacuated and the doctors must handle incoming casualties by themselves, leaving the O.R. and everything else in a mess. When the nurses returns, Colonel Potter announces that there will be an inspection in two days, so Major Houlihan gets very busy getting everything back in order for this.
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?
Hawkeye receives a letter from Colonel Potters wife where she informs that she has paid the last mortgage on their home and asks Hawkeye and friends to throw a small surprise party for Potter to celebrate.
Father Mulcahy must save the camp's honor in a high-stakes footrace against the 8063rd. Hawkeye, BJ, and Hot Lips each bet on it. Meanwhile, Charles tries to help Private Walter Palmer, a patient who suffers frequent verbal abuse from his fellow soldiers due to a speech impediment.
General Addison Collins refuses to accept responsibility for the war games that have mortally wounded his son Curtis, a lieutenant. Charles tries to help Margaret, who develops laryngitis as she is about to meet her hero, Dr. Steven Chesler.
Colonel Potter must decide whether to blow the whistle on an old army chum, Woody Cooke, whose military mistakes are costing human lives. BJ suffers from both an ingrown toenail and from Charles' insistence on playing his Mahler records.