A visiting general, appearing to be more eccentric than the usual army brass and a stickler for regulations, tries to move the camp closer to the front and court martial Hawkeye before they discover that he's completely loony.
Hawkeye and Trapper are planning to leave for Tokyo when an unusual offer comes in to swap P.O.W. patients between the Chinese and the 4077th. After much debate, Henry agrees to send Hawkeye, Trapper, Frank, Radar, and Klinger into enemy territory.
Several wild events happen during a nice spring day in Korea. First, a marine who Hawkeye performs surgery on feels beholden to him. Next, Radar falls for a nurse who's main interest is poetry. Then Klinger receives a letter from his girl Laverne who agrees to marry him. Finally, a young soldier in a catatonic state and with no tags wanders into post-op with a strange fixation for a kitten.
Henry suspects his wife is having an affair, Hawkeye searches for presidents' faces to try to win a pony and Father Mulcahy officiates at a Jewish Bris with the help of a rabbi on a faraway aircraft carrier.
After a run-in with Major Houlihan, Henry is not altogether unhappy when the nurses are evacuated due to a possible enemy attack but soon finds out with rest of the camp just how much the nurses mean to the unit.
Hawkeye records a letter to his Dad, detailing the exploits of a mad Turkish soldier, the loss of a Luxembourg Lieutenant's corpse, and a lieutenant's strong-arm tactics to obtain medical care for a comrade.
While Radar tries to stop the camp from being shelled by their own artillery, Frank finds a wounded enemy soldier wired to explode, Margaret and Trapper get stuck in a supply shed and Henry and Father Mulcahy get blown up in the latrine.
Trapper writes a letter to his daughter, Shirley Temple dances, and the 4077th tries to take a mental break from GIs suffering from hypothermia and post-op bleeding by throwing a benefit picnic for the orphanage.
After Hawkeye makes an insulting remark about Margaret, Frank snaps him with a towel and Hawkeye responds with a nicely placed right cross to Frank's eye. Hawkeye is then placed under house arrest and instead of being treated like a criminal, he is treated like a conquering hero for what he did even to the point of getting some very tasty water buffalo steak and having movies shown in the Swamp. In the meantime, Colonel Reese, the woman in charge of all the nurses in Korea, arrives to observe Margaret and her staff and, for some strange reason, becomes attracted to ...
Hawkeye and Trapper try to unite a Korean medic with his family in spite of Frank's interference and find out that a young GI isn't telling the whole truth about his upcoming marriage to a Korean woman.