Celebrating ten continuous years of Kamen Riders in the Heisei Era of the franchise (1999-2009). Ten separate Kamen Rider Worlds are mysteriously merging together, which will eventually destroy them all! To prevent this, and restore the security of these Worlds, the mysterious Kamen Rider Decade must travel to each and eliminate the anomalies while trying to figure out what caused these mergings to begin with! But... does that also include him destroying all Kamen Riders to accomplish this?