Three thousand years ago, the Sword Demon swept through the Immortal Alliance with a single strike of his sword. After being sealed, he was reincarnated as a young boy named Ajiu. A wooden pendant on his chest suppresses his demonic power, but whenever he gets hungry, that power leaks out and throws the world into turmoil. The four members of the Ning Mountain Sect conceal his true identity and suppress his demonic nature by feeding him enormous quantities of food. When Ajiu descends the mountain to make a living, his masters and senior sisters secretly follow him and look after him. Meanwhile, the Demon Suppression Bureau and the Qingyun Sect launch successive investigations and attempts to capture him. Ajiu is kind-hearted by nature and protects his family and the common people. The black sword of Ning River recognizes him as its master, yet never harms the innocent. With the Venerable of Nine Heavens' Punitive Order arriving in three months, the entire town prepares for battle. The secrets buried for three thousand years and the truth of Ajiu's origins are about to be revealed.