The 4077th Mobile Army Surgical Hospital is stuck in the middle of the Korean war. With little help from the circumstances they find themselves in, they are forced to make their own fun. Fond of practical jokes and revenge, the doctors, nurses, administrators, and soldiers often find ways of making wartime life bearable.
Margaret and her nursing staff are about to be inspected by Col. Bucholz. Meanwhile, Kellye is offended that Hawkeye is attracted to any nurse except her.
It's Halloween at the 4077th, and the staff dons costumes and trade ghost stories. Father Mulcahy discovers a soldier alive that had been pronounced dead.
The Army tries to get a North Korean pilot to defect, and Charles gets a rude shock when he falls for a French nurse with a Bohemian past.
Tired of reminders about Trapper John's skill as a practical joker, B.J. bets Hawkeye he can prank everyone present.
Hawkeye volunteers to deliver the eulogy for a dead nurse that he briefly dated, and belatedly discovers her deep feelings for him.
Posing the theory that people will believe in anything, Charles and Hawkeye start a rumor that Marilyn Monroe plans to visit the 4077th, which gets everyone excited. Meanwhile, B.J. feels responsible when he's unable to rescue a wounded soldier, and is less than impressed when he is presented with a Bronze Star.
Hawkeye and the crew surprise Colonel Potter with a party to commemorate Mildred's final payment on the couple's mortgage.
With the camp facing prohibition, and a severe medical supply shortage, during another heat wave, Hawkeye resolves to lift morale by importing a racy new movie.
When an Olympic runner assigned to the 4077th fails to materialize, Father Mulcahy must save the camp's honor in a high-stakes footrace against the 8063rd.
A United Nations delegation tours the 4077th - a Swede, a Hindu, and a British officer - and each leaves a lasting effect on the men and women of the camp.
The 4077th faces a sleepless night as Charles's snoring keeps B.J. and Hawkeye from counting sheep. Meanwhile, Colonel Potter discovers that his son-in-law, Bob Wilson, has had an affair.
A military strategist refuses to accept responsibility for the war games that have mortally wounded his own son. And Margaret develops laryngitis, as she is about to meet her hero, Dr. Chesler.
Potter must deal with an old Army friend who is getting his own soldiers killed through his incompetency.
A wounded GI learns a painful lesson when he forms a recovery room friendship with the enemy soldier he's critically wounded. Soldier: "My boots. All he wanted was my lousy boots. His feet were freezing. I'd have done the same thing. He was just a guy like me, and I shot him. I killed him, for a pair of boots. How can I ever look at a pair of shoes again without thinking of him?"
Margaret and Hawkeye work on a time capsule to commemorate their time in Korea; Rizzo and BJ goof around with a fake hand grenade; Klinger becomes smitten with a young, pretty Korean war criminal.
Hawkeye is sent to a mental hospital; a freak accident causes Father Mulcahy to lose his hearing; Margaret worries about her post-war plans; Charles run across a band of Chinese musicians; BJ is sent home, much to Hawkeye's dismay; Klinger decides to stay in Korea to marry Soon-Lee; a ceasefire is declared, ending the war.