Shusei Murai, the grandfather of Saka's husband, is 70 years old. He is a perverted old man who is still energetic and has an abnormally strong sex drive. Since his wife passed away five years ago, he has been frustrated every day due to the lack of an outlet for his sexual desires. He plots to make his granddaughter-in-law Saka his own by acting like a frail old man to gain her sympathy. He fakes a burn injury as an excuse to have Saka, who is a nurse, take care of him...
