At the 4077th Mobile Army Surgical Hospital (M.A.S.H) unit in Korea, two army doctors by the names of Hawkeye Pierce and Trapper John McIntyre receive some exciting news in the mail. Their Korean house boy, Ho-John got accepted into Hawkeye's old college. Hawkeye and Trapper decide to hold a party filled with music, dancing, and alcohol to raise money for Ho-John's plane trip to the U.S. They achieve this by raffling off a weekend pass with a nurse, Lieutenant Dish for R&R in Tokyo.

Frank Burns complains about Hawkeye Pierce's disrespect...and Henry appoints Hawkeye chief surgeon, to Burns's shock. The rest of the 4077th "coronates" Hawk while Frank and Hot Lips complain to General Barker. The General's visit provides him with a view of life at the 4077th M*A*S*H unit: camp hijinks, a poker game, and a surgery session. This shows him M*A*S*H has fun but gets the job done.

Sergeant Baker arrives at the camp with his Moose. Hawkeye decides to find a way of getting her away from Baker. He tries ordering him to release her, tries buying her, and then resorts to cheating at cards. He releases her but she won't go, so he tries to teach her how to be independent.

John Hodges, a chopper pilot referred to as The Cowboy because of his gun holster belt and cowboy hat, has been hit in the shoulder, and arrives at the 4077th. He is expecting a letter--he's worried his wife Jean at home is leaving him for another man ("She's probably off with some rodeo rider; she's a sucker for a 10-gallon hat!"). He wants to go home, but Henry refuses, stating Cowboy's wound isn't serious enough to merit a stateside ticket. Bad luck then follows Henry Blake like the seat of his pants: he gets shot at while golfing, his tent gets flattened by a driverless jeep, and the latrine explodes while he's inside. The Cowboy offers to fly Henry to Seoul and then threatens to shove him out! The letter finally arives for Cowboy, assuring he is loved. Hawkeye and Trapper uses the radio to convince The Cowboy to spare Henry's life and come down, at which they succeed.

Henry receives a citation for the camp achieving the best efficiency rating, and then General Hammond reassigns him to Tokyo. Frank then changes the camp to be more military, and he confiscates Hawkeye's and Trapper's still. They use forged passes to go to Tokyo to convince Henry to come back and end up pretending Radar is sick.

A rash of thefts breaks out in the camp. Missing pieces include Frank's silver picture frame, Margaret's hair brush, and Trapper's watch. The camp is searched and everything is found in Hawkeye's locker. Everyone thinks he did it. Hawkeye manages to announce to the camp that the items will be dusted for prints to identify the real thief, and catches Ho-Jon. He needed money to bring his family from the North, and to bribe border guards.

Hawkeye moves a wounded North Korean soldier into The Swamp, rather than let him be shipped out before he's stable. During the night he and Trapper play Dracula, and siphon off a pint of Frank's blood. The soldier then contracts hepatitis, so they have to test Frank without him knowing, and have to keep him away from Margaret and the patients.