Seven individuals, including park guest Takeshi Kuranari, become trapped inside LeMU, an underwater marine theme park located 51 meters below the surface, after a sudden accident. A system failure causes nearly half of the facility to flood, cutting off communication and escape routes to the surface. The park is under constant assault from severe water pressure, giving the survivors a limited time to find a way out before the facility implodes. As they struggle to survive, questions arise about the nature of the accident and whether their presence in LeMU was intentional.
