Movie War 2010 is split into three parts. The Kamen Rider Decade portion of the film, written by Shoji Yonemura, is titled Kamen Rider Decade: The Last Story. It follows the series cliffhanger ending at the climax of the Rider War. The film is billed as the "True Ending" and was originally subtitled Decade vs. All Riders. The Kamen Rider W portion of the film, written by Riku Sanjo, is titled Kamen Rider W: Begins Night, taking place between episodes 14 and 15 of Kamen Rider W, investigates the origins of Kamen Rider Double as briefly shown in the cold opening of the series' first episode, referred to in the series as the "Begins Night". The film is described as the "True Beginning" and was originally subtitled Episode Zero. In the final portion of the film entitled Movie War 2010, a convergence of the two films that brings the casts and characters of Decade and W to finish the fight with Super Shocker together.
Much like with the Kamen Rider Kiva film Kamen Rider Kiva: King of the Castle in the Demon World, Kamen Rider Decade: All Riders vs. Dai-Shocker had a series of Internet and cellphone spin-off films titled Kamen Rider Decade: All Riders Super Spin-off (ネット版仮面ライダーディケイド オールライダー超スピンオフ Nettoban Kamen Raidā Dikeido: Ōru Raidā Sūpā Supin'ofu). Thirty of these short films were made, taking place on the World of Net (ネットの世界 Netto no Sekai), with the first aired on July 17, 2009. There were main five different formats for the web movies, Petition! (陳情! Chinjō!) , Check! (チェック! Chekku!), For Real! Heisei/Shōwa Rider Athletic Meet!! (ガチ！平成/昭和ライダー運動会!! Gachi! Heisei/Shōwa Raidā Undōkai!!, Which One! (どれだ! Dore da!), and Transform! (変身! Henshin!).
Kamen Rider Decade: All Riders vs. Dai-Shocker is the film adaptation of the 2009 Kamen Rider Series Kamen Rider Decade. As Decade is billed as the 10th anniversary series of the Heisei period run of the Kamen Rider Series, the film features all ten of the lead Heisei Kamen Riders, as well as all of the Shōwa period Kamen Riders, leading to a total of 25 Riders (with three secondary Riders and three Diend-summoned Riders).
Taking place after the events of Kamen Rider Decade episode 15, under the impression that they saved the World of Den-O, Tsukasa Kadoya and company begin their journey to the World of Kabuto when they are halted by Sieg who presents them a manuscript that detailed the legendary Oni Conquest with Momotaros' image on it. As this occurred, the Tarōs mysteriously vanish from the DenLiner as they are about to help Kotaro Nogami out with the true threat to their world.