Ryouma Echizen and the Seishun Academy Boys' Tennis Team are invited to participate in an exhibition game aboard a luxury cruise ship by its owner, Hikomaro Sakurafubuki. When they arrive, the boys are shocked to discover that Ryouma's adopted older brother, Ryouga, is the captain of the opposing team. During their first games, Seishun easily crushes their opponents, garnering excitement from the cruise spectators. H...