In October 1942, ten months after the attack on Pearl Harbor, ComSubPac directs the American submarine "Greyfish", under Lieutenant Commander Barney Doyle (Glenn Ford), to the convoy containing the "Shinaru", one of the Japanese aircraft carriers that led the attack. Doyle also receives word that the target's escort includes a transport ship, "Yoshida Maru", carrying all the American prisoners from the camp in the Philippines where his wife and child were being held. (Flashbacks show that Jane refused to leave Manila.)