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!
No one seems to understand Nakami. His nights are restless, his days sleepy, and his time at school is isolating. Yet all that seems to change when he encounters his carefree classmate, Magari, dozing off in their high school’s abandoned observatory. Not only is Magari friendly, she’s also a closet insomniac. Together they find solidarity in their shared condition, using the observatory to nap as needed. When their unsanctioned use of the space is discovered, the only way to save their refuge is to revive the school’s long defunct astronomy club. As they work together and get to know each other, their bond grows ever stronger, but hidden truths threaten to cut their budding friendship shot.