Reiko has recently started gaining weight and became concerned about her body. Trying to lose weight, she began searching for effective methods and one day came across "kaatsu training" — a form of restricted blood flow exercise. Without proper compression bands at home, she came up with the idea to use hemp rope instead. Reiko decides to try kaatsu training on herself, ultimately asking her son Kenji to tie her up. Kenji binds his mother without fully understanding why, but as the ropes dig into her flesh, he becomes captivated by the sensual curves of her mature body, awakening uncontrollable desire within him.