Satoru lost his mother when he was young and now lives with his Dad and his new wife: Kyoko.
One day, Satoru watches his Dad and Kyoko having sex, and from that day on he has been having trouble sleeping (and erections).
Kyoko finds out and attempts to teach him sex education… However, wanting to help, she goes a little too far.
Nagae is really going there. And Machimura Kyoko was incredibly sexy, what a performance.