Xu Yuan appears to be a useless young master of the Xu family in Tianxuan City, stuck at the Qi Entry Realm for eight years. In truth, he is Fist Thirteen, a body-tempering powerhouse from the Northern Domain. A mysterious white-robed female immortal teaches him the Longevity and Imperishability Art and the Fist Canon in his dreams, allowing him to open eight flesh-and-blood heavenly realms. Daoist Fengxian of the Hehuan Sect discovers his secret, setting off a storm across the Northern Domain. By day, he disguises himself as an ordinary nobody; by night, he wears a ghost mask to fight enemies and uphold justice. Burdened by his origins in the War God Manor and the pain of his mother's disappearance, he ventures into the Great Wilderness to compete for the legacy of an ancient sect, hoping to refine the Blood of Longevity and live openly as his true self.