Morihito Inoue

In a small hot spring town in Japan, a ferocious ancient shark reawakens and begins terrorizing the local hot spring facilities. As the threat escalates, the townspeople band together to protect their beloved town from the menacing predator, leading to a fierce and thrilling battle.

A monster appears underground in Atsumi City, S Prefecture, a city famous for its hot springs. The supply of hot springs has stopped, putting the town's tourism industry in danger. Suffering from unpopularity, Mayor Kan'ichi Mangaki personally pilots a drill machine developed by his late father, Tetsuzaemon Mangaki, and heads underground to defeat the monster. Awaiting him there are giant monsters and invaders. "Fight, Kan'ichi!" When you shout, the drill machine transforms into a steel warrior, the Bass Diver! Can the young second-generation politician defeat the monster, save the town of Atsumi, and restore his approval rating?

A massive swarm of clone sharks rises from hot springs and volcanoes, leading to a jaw-dropping showdown that throws all of Kyushu into total chaos! The story follows a high school girl and her bond with an Onsen Shark.