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!
With dreams of diving abroad, Tsuneo gets a job assisting Josee, an artist whose imagination takes her far beyond her wheelchair. But when the tide turns against them, they push each other to places they never thought possible, and inspire a love fit for a storybook.