After getting an A on his exam, fiendish Jun-kun forces Kaya to wear her school's gym bloomers. Kaya allows him to do whatever he wants as a reward and they intend to spend the night together as Izumi is off on a trip. 

Unexpectedly, Izumi's trip was canceled and comes home to find Kaya in her bloomers. Izumi finds her sexy in her bloomers and decides to fuck. Hilarity insues as Jun-kun needs to stay hidden from Izumi and watch him do what he wished to do to her.

Kaya takes it upon herself to go along with it as to not rise suspicion from Izumi. Izumi recalls the good ol' days when they skipped university classes to have sex. They got married after learning Kaya got pregnant. After cumming inside her Izumi comments that he's glad Kaya is still a pervert despite seeming apathetic recently. 

Jun-kun nuts to them having sex in front of him. His first cuckholding.