Karen Tojo, the live-in secretary at the company president's house, has a boss who enjoys sexual harassment and frequently fondles her big, shapely ass. His son, Shota, often witnesses these scenes and develops a strong fascination with Karen's gorgeous backside. Abusing his position, Shota begins pulling increasingly lewd pranks on her. In the bathroom, surrounded by steam and bubbles that reveal her pale, silky skin, he gropes and massages her big ass. He even brings his friend Masato into the fun, joining forces to torment her with sex toys. As night falls, their antics grow bolder—catching her off guard, Shota ends up shooting his creampie deep inside her.