Scuba-divers plot a bank robbery on lovely Catalina island in this caper movie. After the heist, the thieves dive into the see with their booty and swim for their getaway boat. Unfortunately while fleeing, the ring leader's chief assistant suffers a heart attack; more trouble ensues when a police bullet punctures the leader's air tank. Though he is now starving for oxygen and tired, the villain keeps going. Just as he is about to board the boat, he is sucked in to the crafts powerful propeller and dies a grisly death.