Miu, a high school student, adores her older brother Keiichirou and considers him to be the kindest and gentlest person in existence. However, when Miu discovers a suspicious pervert in the area, she discovers that the perpetrator is actually a couple who resemble the description. In a state of shock, Miu flees back to her home, only to learn that the individuals involved are none other than her brother Keiichirou and his demon sex slave, Manimani, who was summoned from the depths of hell using Keiichirou's magician powers. With her perception of her brother now shattered, Miu is at a loss for what to do next.
