Otani, who shares a room with his best friend, is asked by his friend to look after his younger sister, Misaki. At first glance, Misaki is a small beautiful girl at 142cm, but she is actually quite a brat! She tempts Otani by showing off her underwear and nipples. There's no way he can resist this! His reason explodes and he ends up having sex with the cute little devil all day long!