Nurse Lt. Ruth McGara is assigned to a Mobile Army Surgical Hospital (MASH) unit near the front lines of the Korean War. There she meets and is roughly romanced by Major Jed Webbe, one of the unit's surgeons. Webbe is pushy and seems to care only for momentary pleasures, but McGara falls for him just the same. Their romance blossoms in the midst of overwhelming numbers of casualties, threats from the enemy and from the weather, and emergency evacuations that test the mettle of even a unit whose very name suggests quick mobility.