The King of Assassins in the dark underworld and the leader of the "Wolf Organization"—the legendary 'Wolf King'—fails a mission for the first time. Heavily wounded, he retreats to China. To investigate the secret of his parents' origins and fulfill his father’s dying wish, he becomes a "live-in son-in-law" for the Feng family. He is no longer the Wolf King; he is now Jiang Hao. A year ago, the dark world declared that the 'Wolf King' had fallen after his failed mission. But now, Jiang Hao has hidden his legendary identity within the city, ready to unleash a frenzy of revenge and slaughter!