Confronting a mysterious enemy, the Pteranodon Yummy, Kamen Rider W receives aid from Ryu, who has infuriated Akiko by being too busy to attend her wedding! Akiko demands to know why he even became a Kamen Rider in the first place and the Pteranodon Yummy as it uses the Memory Memory on her to give her the answer to her question. Meanwhile, at the Kougami Foundation, Kousei Kougami talks of the most avaricious man in Japan, Oda Nobunaga, whose final resting place was found. With Doctor Maki overseeing the process, Kougami commissions the creation of a Cell Medal homunculus based on Nobunaga himself. Later, Kamen Rider Core begins to destroy the area as Kamen Riders OOO and W team up to fight the enemy. However, Kamen Rider Core proves too powerful and the two go underground to destroy the Gaia Memory’s source of power to even the odds.

Movie War Mega Max featured the first seven Kamen Riders (Kamen Rider 1, 2, V3, Riderman, X, Amazon, and Stronger) to commemorate the franchise's 40th anniversary. Trailers for the film shown during airings of Fourze also showed the return of Kamen Rider Double as well as a new form for Kamen Rider OOO. Unlike previous Movie War films, where they were divided into 3 segments, Movie War Mega Max is divided into 5 parts. Like previous Movie War films the secondary Kamen Rider of Kamen Rider Fourze, Kamen Rider Meteor, made his debut in the film.

2015 Japanese film directed by Shinji Higuchi

『ネット版 オーズ・電王・オールライダー レッツゴー仮面ライダー 〜ガチで探せ！君だけのライダー48〜』（ネットばん オーズ・でんおう・オールライダー レッツゴーかめんライダー ガチでさがせ！ きみだけのライダー フォーティーエイト）は、2011年3月11日より東映特撮 BBやテレ朝動画などで有料配信のスピンオフネットムービー。『劇場版　仮面ライダーキバ　魔界城の王』以降制作されてきたネットムービーが夏以外の作品で制作されたのは初である
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