Diver Rankine undergoes basic training by Gascoigne, who says he'll never make officer. Despite this Rankine graduates and is posted to New Guinea to take command of a small diving unit there. As luck would have it, Gascoigne has been posted there as well, and now finds himself outranked. Despite a difficult beginning, the two men learn to work together, especially after being sent to salvage torpedoes from a recently sunk Japanese submarine.