His sister-in-law Reiko comes to stay with him while his wife is away. She smiles seductively and gives him a titjob and a blowjob. Her husband can't take his eyes off Reiko's voluptuous body, but there seems to be something going on. Then a stranger appears and violently assaults Reiko. It seems that he owes the man money. The husband is told to keep quiet, but he is seduced by Reiko and becomes immersed in a lustful affair.