The reason why Satozaki, a problem child who had been refusing to go to school for a long time, decided to participate in a school trip. It was to help Sachiko, a teacher who was more concerned about Satozaki than anyone else. Aiming for the opportunity to take advantage of Sachiko's lascivious big breasts body that not only grabs the eyes of adolescent boys but also captivates their parents and male teachers I was ... Satozaki, who saw Sachiko heading to the open-air bath alone late at midnight on the first day of the trip, rubbed the big Sachiko's bust, which had been undressed at the dressing room, from behind. "Satozaki-kun! What are you doing !?" "It's okay, it's time for everyone to sleep ..." A long, short and unforgettable three days have begun for them.