Ticonderonga no Iru Umi

Based on a children's picture book of the same name. On December 5, 1965, a U.S. aircraft carrier is en route from Vietnam to Yokosuka, Japan. During training exercises off Okinawa, an A4 strike aircraft loaded with a B43 hydrogen bomb falls overboard and sinks. The incident was kept secret, and the plane, its pilot, and the bomb were never recovered. The story continues with Ashika, a boy from a Japanese fishing town, contacted by telepathic whales who bring him visions of fearful seamonsters.