The story follows a group of high school students as they approach graduation, just months away. Each student grapples with their dreams, worries, and inner conflicts as they face crucial life decisions.

All the incidents occuring around the Girls Remix up to this point were part of Sumire Kurono's plan to create the ultimate Kamen Rider. Now that plan is moving into its final phase. Sumire kidnapes Nayuta Mikazuki again. After performing her final surgery, "Kamen Rider Eins" is finally born. Will the Girls Remix be able to get Nayuta back? And what will become of Nayuta, who has become Kamen Rider Eins?

Rikka Isurugi (Chihiro Yamamoto), head of the Fox Clan, is investigating the "White Lotus," a mysterious cult suspected of plotting a rebellion against the Shogunate. During her mission, she encounters Okyo (Kanon Miyahara), a Fuma Ninja dispatched by the Shogun. Their paths converge as they face a formidable common enemy: the Iga Ninja clan, led by Hattori Hanzo (Kane Kosugi), who harbors a deep vengeance against the Tokugawa family. A three-way conflict between the Fox Clan, Fuma Ninja, and Iga Ninja is about to begin.