Twenty years ago, there was a weapon in the world called "Love Silk". It was as thin as spider silk, no different from ordinary yarn, and extremely flexible. Silk is a unique thing from the world, and it is highly poisonous. The poison will develop after a year, and there is currently no cure. If the love thread touches a wound, it will quickly enter the bloodstream. Once the injured person becomes over-emotional, his or her heart will be reversed, putting his or her life in danger.