A young Army nurse, Lt Ruth McGara (June Allyson), newly assigned to the 66th MASH during the Korean War, attracts the sexual attention of the unit's commander Dr. (MAJ) Jed Webbe (Humphrey Bogart). Webbe, who has a drinking problem, at first wants a "no strings" relationship. McGara is warned by the other nurses of Webbe's womanizing ways. Despite these initial handicaps, their love flourishes against a background of war, enemy attacks, death and injury. The relationship deepens and uplifts both characters.