The stage is Asakusa, Tokyo. Middle schooler Kazuki has quit the football club, without telling his childhood friend (or maybe more?) Enta, and is now doing everything he can - no the consequences - to connect with 'that person'. When the delinquent Toi transfers into his class, he and Kazuki end up destroying the local Kappa statue - angering the prince of the Kappa, Keppi, who turns the 3 boys into Kappa by stealing their Shirikodama, the soul-containing organ located in the anus. Now, in order to return to being human, the boys must steal the Shirikodama of the 'Kappa zombies' that have appeared and are feeding on the desires of Asakusa denizens. Can the boys succesfully connect together and defeat the zombies? And if so, what dark secrets will be revealed through the 'Sarazanmai' process? Meanwhile, local cop duo Niiboshi Reo and Akutsu Mabu are the ones behind the "Desire exploitation" process creating the Kappa Zombies. Who are they taking orders from? What secrets do they have