Nana, Yoichi's cute but annoying little sister, watches a horror movie and gets too scared to sleep alone. She crawls into her big brother's bed expecting him to tease and play with her body a little. However, Yoichi is fast asleep. Frustrated, Nana starts playing with his body instead, leading to intense incestuous sex with deepthroat, paizuri, raw pounding missionary and doggystyle until he gives her a creampie, turning their sibling relationship into a secret daily routine