Based on a manga "Go-toubun no Hanayome" by Haruba Negi. In the game, the Nakano quintuplets, protagonist Uesugi Fuutarou, and Fuutarou's younger sister Raiha went to the Nakano's private island during the summer break only for three days and two nights. But due a heavy storm, the group is unable to going back and has to spend 2 weeks in the island.