Jun Xiaoyao is reborn and activates a sign-in system. His first sign-in rewards him with the fully developed Desolate Ancient Sacred Body, setting him on an extraordinary path to defy the heavens. He breaks through realms and becomes invincible at the age of five, humiliates powerful enemies at his coming-of-age ceremony, and later receives the Immortal-Slaying Sword Art personally from the Eighteenth Ancestor. He ventures into a Supreme secret treasure trove in search of treasures, while a Dragon Girl of the Ancestral Dragon Clan enters the hunt to avenge herself. Who will ultimately claim the secret trove remains a mystery. Adapted from the novel Sign In at the Start: The Desolate Ancient Sacred Body by author J Shen.