The former female members of a high school basketball club have gathered for a party in memory of their basketball coach Ando Katsuhito. 39-year-old Enoki Kana, 53-year-old Tsuruga Yuko and 27-year-old Mishiro Akane are noticeably unhappy. Each of them has just suffered an unforeseen incident, prompting them to say with a touch of self-derision that their prime was during high school. Kana’s image as the “perfect stay-at-home wife” has shattered with the exposé on her husband’s affair. Yuko has not only suddenly fallen from the fast track at her company due to allegations of sexual and power harassment, but also discovered that her boyfriend is cheating on her. Akane has been acting as a girl who has it all on social media but become the target of a huge backlash. While the three women belong to different generations and have different personalities, the one thing that they have in common is that they are former captains of the same basketball club.

10 years ago, the “Pandora Box” was found on Mars. On Earth, it created walls that divided Japan into Touto (Eastern Capital), Hokuto (Northern Capital) and Seito (Western Capital) and brought along the Smash, unidentified lifeforms that attack people. Sento Kiryu, prodigy physicist, transforms into Kamen Rider Build to fight the Smash. The Touto government requests his help in deciphering the mystery behind the Pandora Box and the Smash. There is one mystery not even Sento can solve: his own past. The only memory he has left of more than 20 years is the existence of a sinister figure called, Knight Rogue. There is one man who holds the key to Sento’s memories. A prison escapee by the name of Ryuga Banjo, who adamantly denies committing the murder he is accused of. Misora Isurugi who works with Sento, has the ability to purify the harmful components the Smash are made of. Sento transforms into Kamen Rider Build in order to uncover the mystery surrounding the Pandora Box, the Smash and his amnesia. [4]