Ryo spends a weekend afternoon alone while his parents go on a trip. On his way home, he happens to run into his girlfriend's friend's older sister, Rena. Rena, who ran away from home after a fight with her husband, is unable to return to her parents' house, so she decides to visit Ryo's house. Ryo, who has been attracted to Rena's adult sex appeal since he was a child, is so excited that he has wild delusions... Unaware of this, Nurena teases him with her defenseless appearance, but she resists.