On October 31st, 2024, the Great Cataclysmhappned. Ever since, the world has turned into a hell swarming with grotesque monsters. The only ones capable of fighting back were the Chosen Ones, those who possess superhuman powers. K, an S-Rank Chosen One, fought life-and-death battles against the monsters as a dog hired by the organization. However, in one such battle, he loses his life… But when K, who was supposed to be dead, awakens, he finds himself in the body of a baby. What’s more, time has rewound to the year 2020! Somehow, he had been reincarnated 4 years before the "Great Cataclysm" occurred! To stop the impending doom, K once again confronts his destiny!