The sexual adventures of protagonists no longer occur only in Imaizumin’s small apartment, now the girls also have sex with him inside the school. Because Imaizumin’s mother is coming to visit him, Reina, Yukina and Ruri leave him alone for a few days to receive her, a situation that makes him sad as he feels lonely again.

Imaizumin and girls move into a new apartment that is much bigger and cheaper than the old one. Although his new apartment is perfect, an issue arises when his new neighbor turns out to be Risa, Reina’s older sister, who seduces Imaizumin when the girls are not around.