Kamen Rider Fourze was the thirteenth Kamen Rider series in the Heisei period run and the twenty-second overall. It began airing on September 4, 2011, the week following the conclusion of Kamen Rider OOO. The series commemorates not only the Kamen Rider Series’ 40th anniversary but also the 50th anniversary of spaceflight, which began with Yuri Gagarin’s flight in 1961.
The show’s catchphrase is “Switch on youth ’cause we’re going into space!” referencing the Fourze Driver transformation belt which gets its various powers from devices called Astroswitches to conjure attachments to Fourze’s limbs. As with the two previous series, the protagonist of Fourze made his debut in the annual summer film of the show’s direct predecessor, appearing in Kamen Rider OOO Wonderful: The Shogun and the 21 Core Medals.
Amanogawa High School has become the centre of strange happenings, and things only get stranger when the bad boy styled transfer student Gentaro Kisaragi attempts to make friends in his own unique way, reuniting with childhood friend and self-professed space travel otaku Yuki Jojima, all while gaining the ire of loner Kengo Utahoshi.
When the campus becomes overrun with monstrous constructs called Zodiarts, Kengo and Yuki attempt to use the strange devices they have found in the Rabbit Hatch lunar base that they access through a locker on an off-limits part of campus to fight them. However, Gentaro interferes in their plans, in part due to Kengo’s body unable to handle the strains of battle, and uses the devices to transform into Fourze.
Upon learning of other heroes called Kamen Riders, Gentaro creates the Kamen Rider Club whose membership includes Yuki, Kengo, the school’s queen bee Miu Kazashiro, Miu’s jock ex-boyfriend Shun Daimonji, garishly styled social butterfly JK and goth girl Tomoko Nozama.
Later joined by Ryusei Sakuta, a transfer student who transforms into Kamen Rider Meteor, and their teacher Mr. Chuta Ohsugi, the Kamen Rider Club and Kamen Rider Fourze learn of the Horoscopes, an evolved group of Zodiarts who have been orchestrating events on the school grounds to build up their ranks. As the battle escalates, the Horoscopes sets their motions to their final phase of their master plan before Kengo discovers his true existence.