Xia Xun, an ordinary man who, after witnessing Jinyiwei's brutality, an imperial military secret police serving the Ming dynasty emperors in China, decided to stand up for the common folks. His path led him to his future wife and his sworn brother, as well as a prince and his wife. His capability attracted the attention of Jinyiwei top brass. They recruited him into the agency and trained him to become an elite Jinyiwei. In the meantime, the newly ascended emperor ruled with an iron fist and tolerated no dissidents. Seeing the plights of the people, the man began covertly helping the prince to ascend the throne and restore peace to the country.