The film follows the story of Miyuki, a young woman living with her older brother. Miyuki is a bold and obsessive younger sister who has turned her older brother into her personal "Ona Pet." Within the walls of their shared home, she ignores all boundaries of modesty and family, treating him as nothing more than a plaything. The story follows her as she aggressively asserts her dominance, using her brother to satisfy her every whim while he is forced to endure her constant, boundary-pushing provocations.
