This movie's opening foreword and dedication states: "When the Pacific Fleet was destroyed by the Japanese sneak attack on Pearl Harbor, it remained for the submarines to carry the war to the enemy. In the four years that followed, our undersea craft sank six million tons of Japanese shipping including some of the proudest ships of the Imperial Navy. Fifty-two of our submarines and thirty-five hundred officers and men were lost. It is to these men and the entire 'silent service' that this picture is humbly dedicated."