Su Muchen, the Lord of Tianmen, enters the mortal world to fulfill his master's orders, only to have his arrogant fiancée break off their engagement and arrange a new contract. Guided by a physician's benevolent heart, he practices medicine to save lives and help the world. With unwavering righteousness, he sweeps away evil and protects the greater good of his country, winning the devotion of loyal ministers, righteous men, and outstanding heroes throughout the land. As the one-year deadline approaches, undercurrents stir in the mortal world. When will the supreme powerhouse, dismissed and underestimated by worldly eyes, finally reveal his astonishing true identity?