A man named Tsukuda had a girlfriend who was easy to handle because she cared more about him and money than anything else. However, he knew that his sister found her irresistible. Determined to make her his own, Tsukuda sneaked into Ayu's room one night while she was sleeping and threatened her with explicit videos of her older sister that he happened to have recorded out of curiosity. Despite resisting at first, Ayu eventually gave in to his persuasion. Some time later...Tsukuda invited Ayu over to his place where he began preparations to turn her into his personal sex slave by drugging her with aphrodisiacs and training her body accordingly.