In the spring of 1941, sixteen-year-old Toshihiko leaves Amsterdam to attend school in Karatsu, a small town on the western coast of Japan, where his aunt Keiko cares for his ailing cousin Mina. Immersed in the seaside's nature and culture, Toshihiko soon befriends the town's other extraordinary adolescents as they all contend with the war's inescapable gravitational pull.