During World War II, Lieutenant Commander Quinton McHale is the commanding officer of the U.S. Navy PT boat-73 stationed at the Pacific island base Taratupa. In the late spring of 1942, the Japanese heavily bombed the island, virtually destroying the base. Only 18 out of the 150 Navy aviators and Marines assigned to the base survived. With the Japanese patrols in the region too heavy for the Navy to mount a rescue mission, McHale and his men were forced to survive by hiding on the island. Assisted by the native tribes whom they befriend, the sailors live a relatively paradisical island existence. After months of rather leisurely living, straight-laced, by-the-book Annapolis graduate Lieutenant Durham parachutes onto the island. His job is to assume duties as McHale's executive officer and help him get the base on Taratupa back into the action.