As Hawkeye and Trapper are planning to leave for Tokyo, an unusual offer to swap POW patients between the Chinese and the 4077th comes in. Henry, after much debate, agrees to send Hawkeye, Trapper, Frank, Radar, and Klinger into enemy territory. Frank almost botches the swap when he brings a squirtballoon to the exchange. Fortunately, the Chinese Dr. Lin Tam has a sense of humor; he went to the University of Illinois, after all.
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.