Mirai Kakehashi is a young student fed up with a life of abuse from his uncle and aunt who raised him since his parents' death, but is saved by a Guardian Angel called Nasse after attempting to commit suicide. Upon learning from Nasse that his foster parents were responsible for the deaths of his father and mother, Mirai uses the powers she bestowed him in order to confront them and enact justice. However, Mirai's ordeals are just beginning as Nasse soon after informs him that God will retire in 999 days and thirteen candidates to replace him were selected including Mirai himself. To make matters worse, not only can Mirai not refuse to take part in the contest to decide the next God, but among the other candidates there are those capable of anything to win, including killing all the Competitors as soon as possible.