In the third year of the Tianbao Era, operatives of Wolf Squad disguise themselves as merchants amidst the hustle and bustle in the western district of Chang’an city on the eve of the Lantern Festival. The operatives are waiting for the right moment to strike. Li Bi, director of Peacekeeper Corps, is under orders to apprehend the Wolf operatives that have infiltrated Chang’an. This covert operation is foiled, allowing the squad leader Cao Poyan to slip away. Li Bi sends Tan Qi to the jail to bring the convict Zhang Xiaojing, who is sentenced to death, to be tasked with continuing the investigation.