A Japanese Maritime Self-Defense Force (JMSDF) submarine sank in a maritime accident near Japan. Japan was shocked by the news that the survival of all 76 crew members, including the captain, Second Lieutenant Shiro Kaieda, was hopeless. However, the crew actually survived. They were selected as crew members for a nuclear submarine built in top secret by Japan and the United States. Adapted from the manga series "The Silent Service" (沈黙の艦隊) by Kawaguchi Kaiji (川口開治).