He has long coordinated the maintenance of local security, but has been held in prison for violations of the law. The Jingan Department, which is responsible for the security of Changan City, found suspicious people who mixed into the city. Because Zhang Xiaojing was familiar with the personnel and geography of the incident, the Jingan Department specially appointed Zhang Xiaojing to do meritorious service and solve the case. After an investigation by Zhang Xiaojing, it was found that the enemy's plot was to create chaos at the gathering on the evening of the Lantern Festival. Only a few hours away from the Lantern Festival, Zhang Xiaojing must catch the sabotage assassin before the Lantern Festival.