One day, Miyu discovers her older brother masturbating while playing an adult game, and she becomes flustered and intrigued by the erotic scene. She sees his kindness and pure heart, which gradually leads her to act more seductive toward him. Occasionally showing a tsundere side, she acts like a clingy, affectionate child, irresistibly drawing her brother closer. Her behavior unfolds like a dreamy romantic story, making viewers' hearts race with excitement.