His wife went back to her hometown to give birth, leaving Toru behind. Living alone for the first time in a while, he was excited to play pachinko, something he had been banned from doing since getting married, but then his sister-in-law Sena suddenly showed up. She said she was there to help Toru, who must be in trouble being alone. As Sena was cleaning, she showed him her breasts and underwear as if to provoke him, and Toru's sexual desire was at its limit. He tried to escape by going into the bathroom, but Sena followed him...