Zhan Zhao is a court officer who learns of a plot to assassinate Judge Bao. While on holiday he meets a young man named Bai who turns out to be a woman. Zhan Zhao tries to recruit Bai to help him stop the assassination of Judge Bao.

Young Dee Renjie arrives in the empire's capital to join the Supreme Court as police judge of his region. He wants to become a prosecutor. Empress Wu, who is at the beginning of her reign, has commissioned the fierce detective Yuchi to investigate a sea monster that stalks the city at night and makes it unsafe.