In August 1945, near the end of the war, Saburomaru Adachi, a 10-year-old boy, was living on Kamitsujima, an isolated island in the Genkai Sea in Fukuoka Prefecture. The story depicts Saburomaru growing strong with his ama diver mother in Japan after the war!

The turbulent waves of defeat also swept over Kamitsujima Island in the Genkai Sea, where Saburomaru lives. At the same time, the Gotoji group enters the island of Kamitsu, which is the territory of the Genkai family led by Hohoemi Zenjiro. Saburomaru, who was dodging Zenjiro and the brothers' cup in seawater...