[Machine Translation] Tsushima, Nagasaki Prefecture. Gen, a high school student living with his mother and sickly younger sister, spends his mornings as usual. However, his peaceful days are changed by the sudden appearance of an unidentified creature. The strange creature, which eats the islanders and assimilates them, quickly takes over the island...? On that day, the ruler's position will be "preyed" on...! A sci-fi survival story of desperation begins!