Gengensai, o vilão de um feiticeiro que persegue Yukihime, a filha órfã da família Suruga Dainagon, que desapareceu com uma bola contendo o tesouro escondido de 100.000 ryo, e Yataro, um espadachim que protege a princesa.
This film begins with a teacher describing to his students how brave the crew was which died as result of Japan's first submarine accident. The film then follows two of the pupils, one becomes a submarine captain and the other designs submarines.