Riko Miyase was dispatched as a housekeeper to a certain mansion. Living there were a father and two sons. Riko, who decided to live-in and work, got caught up in the schemes of the father and the eldest son and became their sex slave… The salvation for such a Riko is her younger brother, Yuusuke. Riko continues to service the master of the mansion and the eldest son with her own body… Will Riko and Yuusuke's love be fulfilled?
