Nine universes of the previous Kamen Riders merging into one that would destroy all the worlds. Tsukasa Kadoya transforms into Kamen Rider Decade and travels to all of the Another Rider's worlds and eliminate the anomalies in those worlds.
Nine universes of the previous Kamen Riders from the Heisei era merging into one, something that would destroy all the worlds. To prevent this, Tsukasa Kadoya transforms into Kamen Rider Decade and is told that to protect his own world he must travel to all of the other Kamen Riders' worlds (Another Rider's worlds) and eliminate the anomalies in those worlds. Along the way, confronting the mysterious Narutaki and the thief Daiki Kaito, they are joined by Yusuke Onodera of the World of Kuuga and Kivala of the World of Kiva.—Mwd
Tsukasa Kadoya is a civilian with an extraordinary power: to travel inter-dimensional worlds. However, this 'gift' of his has landed him in a situation where 9 preceded Heisei-Kamen Rider worlds have begun merging, and it is kill or die. With this in mind, he dons the persona of Kamen Rider Decade.
Kamen Rider Decade (Masked Rider DCD) is the first 2009 series of Kamen Rider, created as part of the ten-year anniversary for the Heisei Kamen Rider Era. The series is a Crisis Crossover featuring all nine preceding main Riders from the Heisei series. Initially aired alongside the Super Sentai show Engine Sentai Go-onger and then Samurai Sentai Shinkenger, which it shared a crossover with in the Super Hero Time block. The story is as follows: Each Kamen Rider series thus far has existed in its own parallel world. Unfortunately, these ten worlds have begun to be forcefully merged into one, which will lead to their destruction. Tsukasa Kadoya is a (very bad) photographer by trade with Identity Amnesia. When his world literally starts to fall apart around him, he receives the power to become Kamen Rider Decade and is told that to stop the collapse of The Multiverse, he must travel to the other nine worlds and destroy the Kamen Riders that live there, absorbing their powers as his own. Accompanying him on this journey is Natsumi Hikari, a girl whose family runs the photography studio that Tsukasa stays at, and who has been having a recurring nightmare where she witnesses the Rider War: A vast conflict that sees every Kamen Rider fall to Decade. There's also Yusuke Onodera, the Alternate Universe Kamen Rider Kuuga who befriends Tsukasa and decides to join him on his journey across the worlds. As time goes by, it becomes evident that there are more than ten worlds caught up in the dimensional turmoil, and that a dark power lies at its root. Tsukasa also manages to attract some recurring antagonists: Daiki Kaito, an inter-dimensional thief who can transform into Kamen Rider Diend and summon past Kamen Riders to fight for him; and Narutaki, a mysterious man who believes that Decade is the source of The Multiverse's destruction and will do anything it takes to stop him.
