After a late-life divorce, Natsumi Kitahara begins searching for work to start a new life. By chance, she is hired as a housekeeper for a single father, Toshio, and his son, Kenichi. One day, when Toshio temporarily leaves on a business trip, Natsumi is left to manage the household. That night, Kenichi suddenly presses his face against Natsumi's ample breasts, acting affectionate and clingy. Initially hesitant, Natsumi is moved by his warmth and lets her guard down slightly. But Kenichi is no ordinary boy—he harbors the mind of a mature man. Natsumi is forcefully taken right then and there, and from that night on, his hidden, darker personality is revealed. Powerless to protect herself, Natsumi's daily life gradually descends into darkness and distortion. Drawn into Kenichi's twisted desires, she slowly loses all sense of self.