Chu Ning, a prince of a fallen dynasty, joins the Demon Suppression Bureau to raise money for his younger sister's treatment. She possesses the Taiyin Divine Body and suffers from tormenting cold poison. Driven to the brink of despair, he awakens the Ultimate Demon-Slaying System and unlocks the Nine Suns Divine Body. He slays demons to accumulate cultivation, ventures into dangerous lands, and battles monsters and evil spirits, growing rapidly through repeated life-and-death fights. While protecting his sister, he seeks revenge on the Heaven-Swallowing Demon Emperor, who destroyed his homeland. Amid the chaos of a troubled age, he suppresses countless demons and embarks on the path to the pinnacle of power.