Takashi Komiya, the main character who lives with her mother-in-law Yuria who is a blonde foreigner, her neat sister-in-law Anna who has long black hair, and her sister-in-law Lina who is a hidden nerd, aims to get out of the bath of Lina who treats her evilly. Sneak into the dressing room. She threatens Lina to tell her family that she is doing net idol activities silently, and presses her physical relationship. Lina who was resisting at first also cums on Takashi's attack. Treated as an honor student at her home and at school, Anna begins to play every night because of the stress. Anna was seen by Takashi at the moment when she was kissing a stranger in a club. Anna, who holds her secret, culminates in her younger brother's pace while watching the public. One day Takashi, who was able to do what he wanted with his sister-in-law, was enjoying the body of his sister in his room ...!?