Confronting a mysterious enemy, the Pteranodon Yummy, Kamen Rider Double 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… 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. Kamen Rider Core begins to destroy the area as Kamen Riders OOO and Double 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.
The wedding of Ellen and David is halted by a stranger who insists that the bride is already married to someone else. Though the flabbergasted Ellen denies the charge, the interloper produces enough evidence that his accusation must be investigated. Ellen and David travel to the small coastal town where her first wedding allegedly occurred. There, they meet a number of individuals whose stories make Ellen question her own sanity.
Eight years after the battle for the Book of Omniscience, the peaceful lives of Touma, Rintaro, Mei and Kento are troubled by a mysterious new Falchion who can seemingly erase people from existence altogether!
A fragmented look into the memories of two strangers from the same hometown, brought together through a university project.