During the winter in Toyama in 1962, Tatsuo Mizushima is fretting about his feelings for his classmate Eiko Tsujisawa while agonizing about his upcoming high school examinations. When he was little, he and Eiko had heard that in April of a year when the winter has been very harsh, any couple finding fireflies together needs to get married. However, his family's situation does not allow Tatsuo to continue his worrying about such things for very much longer.
In the 12th century, Buddhism was still a relatively new religion in Japan. At that time, one school (Shingon) offered extensive training in complex and very demanding practices which might eventually bring about spiritual purification and realization. Various Zen schools offered students a lengthy path, literally composed of a blank wall and unceasing meditation. Yet another school (Tendai) emphasized complex metaphysics and the study of philosophical systems. Basically, all of them were designed to cater to the few who were able to give up everything else in their lives and focus on liberation, such as scholars and noblemen. In this historical and biographical drama, this is the situation that the young Shinran (1173-1263) discovered when he began exploring Buddhism as an alternative to the violence and ceaseless civil wars that racked Japan at the time.
Five boys escape from their life of bondage on an island 10 miles off Hiroshima, and are picked up in the Inland Sea, drifting in an open boat.
