Expose the Emperor's Secret Letters to the Enemy Nation

A thousand-household commander of the Embroidered Guard, cold-blooded and iron-fisted, is ordered to investigate a case involving a secret letter. He was once Shen Yanqiu's martial arts mentor when she was young and knows she was framed, yet his family has been held hostage, forcing him to hunt down his former pupil. During his investigation, he discovers that the emperor is the mastermind. Torn by conflicting loyalties, he ultimately destroys the emperor's personal seal with his own hands during the confrontation between Shen Yanqiu and Zhaoyang.