Intercepting the transport carrying Foundation X’s new 2nd generation Gaia Memories, the special-ops unit NEVER, led by Daido Katsumi, intend to turn Fuuto into Hell on Earth. With Daido wielding the T2 Eternal Memory and a Lost Driver, granting him power in the form of Kamen Rider Eternal, Fuuto’s Kamen Riders are left powerless as Daido and his allies take control of Fuuto Tower, converting it into a massive laser weapon…

Serving as the true ending to Kamen Rider Decade and revealing the origins of Kamen Rider W, this movie is split into three parts. In "Kamen Rider Decade: Final Chapter", Tsukasa Kadoya fully embraces his title as the Destroyer of Worlds. In "Kamen Rider W: Begins Night", Shotaro and Philip recount the night on when it all began. Elements of both parts converge in the movie's final part, "Movie War 2010" as our heroes fight the forces of Super Shocker.

Set primarily before the events of Kamen Rider W Forever, Kamen Rider Eternal tells the story of Daido Katsumi, the formation of NEVER, the mission that led them to target Fuuto, and reveals just how Daido obtained his Lost Driver and got his first taste of the power of Kamen Rider Eternal. As a mysterious woman retells this story to Phillip and Shotaro, they realize that Daido may not have been the simple monster he first appeared to be…

While settling into married life with Akiko, Ryu is brought into a case involving a woman named Katsuragi Aoi, a member of a pickpocketing ring with most of her teammates murdered from unknown masked vigilantes that Ryu fought as Accel. As the details of the case begin to unravel, Ryu is framed and Akiko believes that he may not be faithful to her. As the clock ticks down, Ryu must solve the case, clear his name, and save his marriage before everything comes to an explosive end!