Shozo Murai is 70 years old and is the grandfather of Sayaka's husband. He is a dirty old man who is still in good health, has a strong sexual appetite, and is abnormally strong. Since his wife passed away five years ago, he has lost an outlet for his sexual desire and has been in agony every day. In order to make Sayaka, his granddaughter-in-law who lives with him, his own, he plans to play the role of a weak old man to gain sympathy. He gets Sayaka, a nurse, to look after him, using the excuse that he staged a burn, but...