As summer draws to a close, the girls make the most of their remaining days with playful adventures. Their carefree routine takes a sudden turn when Suguru Koshigaya wins a coveted prize—a trip to Okinawa! Hastily preparing for the journey, the Asahigaoka group sets off on a three-day escapade. Upon reaching Okinawa and settling into their inn, they encounter Aoi Niizato, the innkeeper's daughter. Despite their similar ages, Natsumi Koshigaya finds herself introspective in the face of Aoi's mature demeanor. As a budding friendship forms, the girls eagerly dive into their sightseeing plans and local experiences, embracing the promise of new adventures.