Riko ★ Schoolgirl, brother-in-law ★ Sober neat man ... Two people who decided to live in the same house under one roof just under the sudden turn due to the remarriage of each other's parents. Riko, a dull brother who suddenly decided to live with her, is a kid. For three days when her parents are absent on a couple's trip, Riko is forced to have sex by being voyeurized by the electric massage machine she had hidden and the masturbation in the room. However, there was a surprising match between the two ... Riko and his brother's sex compatibility was really the best. Tsundere's younger sister in the rebellious period is squid by her brother-in-law who hates it!