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.

Real zombies arrive and terrorize the crew of a zombie film being shot in an abandoned warehouse, said to be the site of military experiments on humans.

Cast and crew reunite to film a spin-off, this time set in Hollywood, boasting more zealous zombies and beefed up with international characters.

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?