A luxury cruise ship has sunk. Onboard were students from an elite school heading for a school trip…. Kirishima Sakuya woke up on the sandy beach of a deserted island. There, taking care of her were three girls: Kaedeko, Natsu, and Suzu, who were considered outcasts at school. As they walked through the jungle of the island to reunite with the other students, they encountered a monstrous creature with human-like parts that preyed on humans…!