In 2008, Hu Xiaoyue, captain of the First Team of the Criminal Investigation Detachment of Hanzhou City Public Security Bureau in Binjiang Province, committed suicide by jumping off a building. His former master Ye Tianyou felt that there was something hidden behind the incident, so he applied to be transferred back to Hanzhou to serve as the director of the Public Security Bureau, trying to uncover the mystery behind his apprentice's suicide.

A week before Hu Xiaoyue committed suicide, he approached his second senior brother Qin Feng, who was the director of the Gutang Town Police Station at the time, and asked him to help him catch dog dealers at a dog farm in the suburbs.