Sumire's sexual desire was so strong that her boyfriend asked her to break up with him. One day, when she was looking for something in her younger brother Katsuhiko's room, she found an unused shoulder ticket she had made for him a long time ago. When her parents were out on a trip and she was masturbating to her heart's content, they found Katsuhiko outside her room, who was masturbating with his own masturbation. She remembers Sumire's ticket, and now she has a condo.