Ten thousand years after his betrayal, Immortal King Mu Yun awakens in the body of a "useless" young man. With hidden alchemy skills and the Slaughter Immortal Diagram, he cures Qin Mengyao, uncovering her Ice Phoenix spirit. As their bond grows, jealous rival Dongfang Yu seeks revenge. Mu Yun embarks on a training journey—unaware assassins await their chance to strike.