Takeshi Hongo is a promising young man with a passion for motorcycle racing. However, his dreams are suddenly ruined when he gets kidnapped by Shocker, the evil secret organization planning to dominate the world. After being remodeled into a cyborg, Takeshi escapes and swears to protect the world from the inhuman monsters.

After being pulled through a door, Shoma finds himself in a peaceful world where Dark Treats do not exist?! In this world, Hapipare still exist, but a young man named Taorin who has Gavv works there. Taorin has no memory of his past, and Shoma decides to help him recover his memories. Meanwhile, a man named Caries begins indiscriminately attacking the town, and the peaceful world is transformed! ...

Granutes are intelligent lifeforms that operate secretly in the human world. They kidnap people for the sake of "Black Market Sweets." As people are attacked one after another by the Granutes, Shoma, a young man from another world, rises up to save the people. Together with the Gochizo, small monsters born from eating sweets, he transforms into Kamen Rider Gavv with a mouth-like belt!

A special preview special released a few weeks before Kamen Rider Gavv's premiere, which revealed new details and unreleased footage featuring the next Kamen Rider, Kamen Rider Gavv.

Takumi's feelings for Gii grow even stronger when they become roommates — but their close bond raises the ire of a jealous classmate.

After the events of the series, Shoma continues his research for "Light Treats" to replace Dark Treats, Hanto continues his research as a freelance writer as keep daily records of the battle of the Kamen Riders, and Rakia remains alone in the Granute World. However, a new incident occurs in the once peaceful human world, forcing Shoma to rush back to the battlefield. What serious abnormality has o...

Takeshi Hongo is a promising young man with a passion for motorcycle racing. However, his dreams are suddenly ruined when he gets kidnapped by Shocker, the evil secret organization planning to dominate the world. After being remodeled into a cyborg, Takeshi escapes and swears to protect the world from the inhuman monsters.