After her beloved husband suddenly dies from an illness, Ryoko is left with a gaping hole in her heart and drifts through each day without motivation. Unable to bear seeing her this way, her adult son Kenji desperately wants to cheer her up. One day, he discovers a scroll among his father’s belongings. He devours every word of the text, titled The Five Rings of Rope Bondage, and learns an astonishing secret: his mother Ryoko has an extraordinary fascination with bondage...