Season 1

Shoma, who comes from a different world, is saved by a boy named Hajime when he collapses from hunger. Shoma excitedly eats the snacks that Hajime gave him, but as soon as he does, Gochizo are born one after another. Meanwhile, freelance writer Hanto is gathering information on the appearance of "monsters" while doing research.

Shoma, who has collapsed from hunger again, is helped by Sachika, who runs an anything-and-everything general store, and treats him to lunch and snacks. Meanwhile, Hanto discovers information about Gavv on social media and starts interviewing witnesses...

After leaving Sachika's house, Shoma encounters Sujimoto. Upon seeing Shoma's strength he offers him a job. Meanwhile, Hanto asks Sachika to look into sightings of Gavv and the Granutes.

After accidentally trying to eat a vegetable in their garden out of hunger, Shoma is invited into Ryoji and Mutsuko's house. Hanto goes to Suga's laboratory in order to learn more about the Granutes.

Shoma collapsed from hunger and was saved by a mysterious monster. Is it a new Granute? Shoma wakes up and transforms into Gavv, but his movement was halted by an unexpected reaction: "The surgery was a success!" Who is this monster?

Shoma starts a new life at Sachika's "Happipare". Meanwhile, Suga has succeeded in developing an item that can transform a person into a Kamen Rider, and asks Hanto to try it out.