One Year Ago, the city was threatened. Threatened by a mysterious world known as Mirror World. Within the reflections of everything, strange monsters lurked, devouring man and woman to sate their own hunger for life. And within the battle, 13 warriors wielding their power did battle in order to obtain their own desire. But in the end, two Kamen Riders stood. Decade. Diend. The war ended with no one winner, and the menace known as Shiro Kanzaki was deprived of his chance to make things right. The Mirror World was locked down, and the monsters faded. Mirror World was no more… However… "I'm live on the scene of the crime," The reporter noted, "Yet another mysterious disappearance has occurred. The second spree of disappearances in two years, the first being just last year. We have yet to find the reason why." Yes, it was another disappearance. Much like those in the Rider War… Decade? Diend? You ready to party?