I want to tie my mother down!

Sudden news of his death. Ryoko, who lost her beloved husband to death by illness, suffers a huge hole in her heart, and spends her days in a lethargic way. Unable to see Ryoko, his only son, Kenji, wanted to somehow cheer up his mother. One day, Kenji finds a scroll from his father's belongings. Kenji devours the scroll with the words "Bondage Olympics" written on it. And Kenji knew. The fact that her mother, Ryoko, has an unparalleled interest in bondage...