Set in a ruined, monster-infested post-apocalyptic Japan, fifteen years after a global cataclysm known as the Collapse, the narrative follows two distinct yet mysteriously intertwined storylines.In the first storyline, a resourceful young girl named Kiruko is hired by a dying woman to escort a teenage boy named Maru across the ravaged wasteland to a destination known only as "Heaven." Maru possesses a unique, supernatural ability: his bare hands can effortlessly kill the bizarre, grotesque humanoid monsters—known as Man-eaters—that terrorize the remnants of human
civilization. Driven by a dying wish, Maru's primary motivation is finding a boy who looks identical to him. Along their arduous journey, the pair navigates treacherous landscapes, encounters dangerous cults, and survives brutal skirmishes, gradually developing a deep, protective bond amidst the bleakness of the outside world.Parallel to this journey is the isolated existence of Tokio, a teenager who lives inside a pristine, walled facility alongside other children. Tended to by advanced robotic caretakers and human overseers, these youths are shielded from the harsh realities of the outside world. However, Tokio becomes increasingly restless and curious about the mysterious "outside," especially after receiving a cryptic message on a tablet asking if she wants to go outside. As teachers enforce strict rules and suppress growing dissent, bizarre anomalies begin to surface within the pristine Eden. Children start developing strange physical mutations, and one student discovers a horrifying truth: the outside world is not just a myth, but a decaying wasteland that their facility was explicitly built to outlive.As the dual narratives progress, subtle clues suggest that Heaven and the outside world are intrinsically linked across time and space. The facility’s leadership harbors dark secrets regarding the origin of the Man-eaters, hinting that the grotesque monsters roaming Maru and Kiruko’s world may be the tragic, mutated end-products of the children inside the walls.Driven by an unrelenting desire to uncover the truth, Tokio seeks a way to escape her gilded cage, while Maru and Kiruko draw closer to their ultimate destination. Their converging fates promise to unravel the mysteries behind the apocalypse, testing the limits of
human resilience, identity, and morality as the boundaries between Heaven and Hell begin to dangerously blur.