The story follows modern military archaeology PhD Xu Chen, who, while surveying the tomb of the Emperor of the Great Qian Dynasty, accidentally travels back in time to the Great Qian era and becomes a eunuch. It is then that Xu Chen remembers the true identity of the original person whose body he has inhabited: he was originally the son of the Northern Marquis' family, Xu Chen. However, the Northern Marquis was falsely accused of treason, and his entire family was executed, leaving only Xu Chen alive to enter the palace as a eunuch. The elderly eunuch who was responsible for Xu Chen's castration, out of gratitude for the Northern Marquis' past kindness, deliberately spared Xu Chen's life. Xu Chen is suddenly summoned by the Emperor. Thinking the Emperor, who has executed 28 eunuchs, is a cruel tyrant, Xu Chen, now occupying the body of the son of the Northern Marquis, plans to take revenge for his family.
