Keita is living alone away from his parents. One day, he receives a phone call from his mother, Yukine, for the first time in a long time. "Tomorrow... Dad will be away on a business trip, so why don't you come over?" Hearing this, Keita immediately understands his mother's feelings. (Mom wants to have sex with me!!) And then, upon returning home for the first time in several years... as soon as he opens the front door, Keita and Yukine touch each other's skin. Having sex for the first time in a long time, Yukine climaxes countless times. Of course, the day doesn't end with just that sex...