After receiving a text message offering to fulfill any of his wishes, high school student Gorou Ono successfully enacts his perverted fantasies with classmate Sawa Honoka. However, to his dismay, the granter of his wish materializes in the form of a demon named Lall. She informs him that he is now part of a game that will determine the next God of the world. As Gorou struggles to come to terms with this reality, Sawa attacks him with a giant sword, revealing that she also is part of this twisted competition for the divine throne. Every participant of the game receives a special power, and Gorou manages to kill his classmate with his ability: the Holy Book of the Fool. But this technique comes at a cost: Gorou's life gets worse every time he uses the book. As he learns more about this seemingly absurd competition, Gorou must find allies and learn how to use his newfound power before he loses everything.

After the mysterious disappearance of one of its participants, the battle meant to name a successor to God is brutally interrupted, leaving behind a trail of destruction and shaking the world. Twelve years later, while the former contestants in the divine competition struggle to fit in society after they were turned into semi-permanents—beings unable to age—Lall refuses to let go of her brother, who has been forgotten by everyone. Determined to resurrect her brother—the only one she sees fit to sit on the heavenly throne—Lall steals her his cellphone from a cult run by a past competitor, which accidentally restarts the competition. Helped by her classmate Eko Sasaki, Lall will show no mercy to prevail against her enemies in her efforts to finally see her brother again.