Monster or human... What sleeps deep in the darkness? All adults on board the Leviathan are dead, and only two students know that help will not come. Should they inform their classmates to collectively find a way out of this desperate situation? Or should they, on the contrary, keep to themselves information on the cryopreservation unit at the heart of the ship, which can only fit one person and is their only chance of survival? Futaba convinces Kazuma to keep quiet, but due to an accident, everyone ends up learning the unfortunate truth. Now, nothing can prevent the survivors from killing each other until the last one standing...