It's a new school year at the local Junior High School i Kamakura. The school year starts off with a new transfer student Ryoichi Kyogoku who joins the 8th grade class. He has been ordered to join the school, and use his special gift of telepathy and take over their school. This boy who happens to be handsome, and be a charismatic person, gains popularity, and using his powers takes over the entire school, except for Seki. This begins a war to regain their freedom for their school and themselves.
One year ago, Yūta lost his father in a car crash. Now in the 6th grade, Yūta goes to catch beetles in a dam near a mountain, a place he often went with his father. There, Yūta meets a strange old man, and while walking in heavy rainfall, slips and blacks out. When Yūta awakes, he sees a child, Saeko, who shows him a village from the past. A precious summer vacation for Yūta begins.
Serving as the true ending to Kamen Rider Decade and revealing the origins of Kamen Rider W, this movie is split into three parts. In "Kamen Rider Decade: Final Chapter", Tsukasa Kadoya fully embraces his title as the Destroyer of Worlds. In "Kamen Rider W: Begins Night", Shotaro and Philip recount the night on when it all began. Elements of both parts converge in the movie's final part, "Movie War 2010" as our heroes fight the forces of Super Shocker.
Inspired by her grandfather's stories, young Shinko embarks on wild flights of fancy about the history of the little town she lives in. But dreams can't fend off the realities of growing up.