Muraii Shouzou, grandfather of Saka's husband, aged 70. A lecherous old man who is still energetic and extraordinarily virile, with an abnormal level of sexual desire. Since his wife passed away five years ago, he has lost an outlet for his sexual urges and has been living in frustration every day. He plots to make his granddaughter-in-law, Saka, his own by playing the part of a frail old man to elicit sympathy. Using a self-inflicted burn as a pretext, he asks Saka, a nurse, to care for him...