On the Mid-Autumn night, General Yuwen Hongce (a fox immortal) was ambushed in Sairengu Valley with his entire army destroyed. Swearing to uncover military corruption, he went into hiding. Meanwhile, official's daughter Wen Dingyi, framed by her father's treason accusation, lost her family and disguised herself as "Mu Xiaoshu" (disguised as a man) to become an executioner's apprentice. Eight years later at a public execution, Xiaoshu narrowly escaped death when rescued by Hongce, unaware that she was the daughter of the traitor who colluded with Wudi, while she gazed at Hongce - the royal prince responsible for her family's destruction.