Shigeru, whose body has weakened and who needs nursing care, lives with his son and wife, Tamaki and Toshifumi. Shigeru tends to feel depressed about his disabled body, but one day he witnesses his son and wife having sex and realizes that his penis becomes erect. Shigeru, disguised as a frail old man, engages in sexual acts with Tamaki, who cannot refuse him, and before long...