Students from Hosho Academy High School were aboard a plane when it crash lands under mysterious circumstances. The heroine, Oribe Mutsumi and her classmates wash ashore on an island. The surviving passengers decide to wait for help to come, but the island turns out to be inhabited by giant insects. Mutsumi wakes up on a beach and finds her classmate Matsuo Ayumi. They use their wits to procure food. Believing that help will come in three days, they decide to endure until then.