Riko - a female student, brother, a neat, neat man ... The two decided to live in the same house under a roof only under the sudden turn due to the remarriage of each other's parents. Riko, a dull brother suddenly decided to live with her, was a child. During three days when her parents were absent during the couple's travel, Riko was forced to have sex by fulfilling the eye of the electric massage machine that she hid and masturbated in the room. However, there is a surprising match between two people ... Riko's sex compatibility and her brother are really the best. Tsundere's sister in the rebellious period was hated by her brother -in -law!