The nurses return from evacuation to find that the doctors have left the camp a mess. Potter announces an inspection in two days, so Margaret and the nurses try to get everything reorganized. Nurse Kelly is mad at Hawkeye for ignoring her.
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.
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.