After a catastrophic event, a group of people live inside a sealed enclosure, cut off from the outside world. They survive on a strict daily ration of bread and milk supplied by a mysterious religious authority that enforces absolute obedience and forbids escape. Among the inhabitants are siblings Reina and Sena, whose quiet routines are shaped by fear, faith, and unspoken doubt. When they meet Kiryū, an outsider who questions the logic of their confinement, cracks begin to form in the community’s beliefs. Together, they plan to cross the forbidden boundary, driven by curiosity and a longing for freedom. As they venture beyond the walls, they discover that the truth about the world — and about the system that controls them — is far more unsettling than they imagined, forcing them to confront the cost of belief, survival, and choice.