The background of the case is set in 1994. In the tide of the times, people's hearts have fluctuated with it, laying a unique background for the occurrence of serial murders.The time when the case was solved was in 2012. Eighteen years have passed by, the aging police, the families of the victims who have emerged from grief, and the truth that has always been hidden in the shadows. The development of the case is full of a sense of fate and the times, and every one of them...Every detail tugs at the audience's heartstrings.In this drama, we will follow the footsteps of police officer Lao Ran and his apprentice Zhao Gan'e, and go deep into the alleys to explore the traces of the serial killer.