Suiminji Harenchi Shoukougun

Souta is a somewhat impudent young man who finds himself with an unexpected visitor: Saki, a black gal who comes to his house as a helper and tutor. She tries to encourage him to study, but Souta is reluctant to follow her instructions.

When Saki falls asleep on his bed, Souta sees an opportunity for mischief. As he plays a prank on her, he realizes she does not wake up. His curiosity gets the better of him, and he begins to explore a more naughty prank, leading to a situation that tests boundaries.