Ataru, a young man, harbored uncontrollable excitement every day toward his stepmother, Chisa, his father's new wife. Chisa was youthful and beautiful, with an H-cup voluptuous figure that constantly captured his attention. Her appearance stirred deep emotions within Ataru, awakening unbearable desires. With his father frequently away due to work, Chisa often found herself alone at home, indulging in self-pleasure. Learning of this, Ataru could no longer resist the urge to simply peek—he made up his mind one night to sneak into Chisa's room while she slept. That night, his inner darkness drove him forward, leading to an inevitable encounter with her body.