On December 6, 1941, Captain Yamanada of the Japanese aircraft carrier "Hiranamu", orders full steam ahead for Pearl Harbor. His ship encounters and sinks an American yacht and the single survivor, Sue Curry, is rescued by an American submarine, the "Sea Serpent", commanded by Commander Chris Warren. He hears her story and attempts to radio a warning to Pearl Harbor. Yamanada, hearing the signals, orders the airlines jammed, and then sends his son into the air to sink the sub. The attack fails, ...