At the end of 1997, Lao Zhang, a policeman from the Fenghe Police Station in Xi'an, who was out on a case, was involved in a car accident and his Type 64 pistol was stolen. In April of the following year, US President Clinton would visit China, and his first stop would be Xi'an. The Ministry of Public Security ordered the Shaanxi police to solve the case by the end of March. The Eighth Division of the Xi'an Public Security Bureau was ordered to solve a series of gun cases, but there was no clue about the 12.1 gun case. At this time, the murderer had used the gun to commit multiple crimes in Xi'an, and many people died. The arrest net was spread out in the surrounding areas, from Ningxia in the west to Shanghai and Hubei in the south. The murderer, like a trapped beast, finally lost his footing. The main culprit was captured after fleeing to Beijing, and the main culprit Dong Lei (played by Wang Shuangbao) was executed in Wuhan. At this time, the time required by the Ministry of Public Security to solve the case was two days earlier...