At the turn of the Qing Dynasty and the Republic of China, Lin Mengchen, the sole survivor of her family's ruin, is sold into a ghost wedding. She's rescued by Xiaosheng, an assassin from the Blood Sacrifice Hall, and they live as brother and sister. Ten years later, while Xiaosheng hides his dual identity as a businessman and assassin, Mengchen secretly joins the Blood Sacrifice Hall, becoming his disciple.