To keep using their school's abandoned observatory as a refuge, two sleepless high school students decide to revive the defunct astronomy club.

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! The two struggle to restore peace and arrive at a huge Candy House. The two are on the verge of grasping something, but Caries transforms with an unknown Gochizo and corners Shoma and the others! What is the soruce of the overwhelming power that this most terrifying enemy has obtained?! What are Taorin's lost memories?!

Sakamichi Onoda is a high school student. He is an otaku, who loves animation and he is also a loner. Although he isn't good in sports, he decides to enroll in the bicycle racing club. Unexpectedly, he finds that he has a talent for bicycle racing. For the first time, he has a friend. Sakamichi Onoda exceeds his limits and finds pleasure in the sport of bicycle racing.

Granute, secret lifeforms, kidnap humans for "Dark Market Snacks." Shoma, from another world, transforms with Gochizo, a sweet-eating monster, into Kamen Rider Gavv via a mouth-like belt to stop Granute's attacks and save people.

Kamen Rider Gavv: Final Stage is the stage show of Kamen Rider Gavv.

Filmed version of the stage show performed May 3-4 2025.