Asahi and her friend Yamato attended an exclusive event together as test players for a new game by the mobile-game company "Sky Nova." The group of test players was diverse in age, ranging from ordinary teens like Asahi to popular idols. The company took everyone on a cruise to explain the rules of this island-based, treasure-hunting survival game. Suddenly, during the presentation, all participants lost consciousness. They woke up on a real island wearing a strange watch displaying the words "Game Start." Now, they are all trapped in this survival game, which has become all too real and deadly!