While spending a summer day at the department store, Suguru Koshigaya wins the lottery's grand prize-four tickets to Okinawa. Filled with awe and excitement, the girls of Asahigaoka do various things to prepare for the trip. From practicing how to ride on an airplane to buying travel essentials at the convenience store, they do everything beforehand so they can enjoy their time in Okinawa to the fullest extent. A departure from the familiar scenery of Asahigaoka is a new experience for Renge Miyauchi, but that does not stop her from pondering how her perspective of the world may change. As the day of the trip draws near, a promise is made.