One day, the Zhangcheng Public Security Bureau received an unsigned envelope addressed specifically to Lu Feng, captain of the bureau's criminal investigation team. There was no sender's name or return address. It seemed to have appeared out of thin air, and the security cameras hadn't caught anyone delivering it. The events shown in the photographs began playing out in real life. When he took a closer look, he realized that every case was connected, entangled with the rest. It was as if this world had been bound together by an iron chain...
Then one day, he discovered that something that had happened before was suddenly happening all over again...
