Ren Jiutian, whose original name was Cang Tianyao, was the youngest son of the Emperor of Heaven. He received auspicious signs from the sky when he was born, and the heaven had high hopes for him. However, a hundred years later, his immortal power was mediocre, his temperament was indifferent, and he had no interest in heavenly affairs. Compared to the prominent status of his brothers, Cang Tianyao is more like an idle idler. The only thing that makes the immortals talk about it is his affectionate attachment to Lian Anran, the orphan of the Fire Lotus clan.
When the orphan of the Fire Lotus tribe was accidentally in danger, in order to save Lian An Ran, Cang Tianyao did not hesitate to break into the legendary hidden mountain where no one could survive, in search of life-saving fairy grass. In the hidden mountain, he glimpsed three gods. The three gods deeply appreciated his courage, but they also secretly set up a trap for him to lose his three souls and seven souls. Cang Tianyao was nearly dead when he returned to heaven with the fairy grass, and his soul flowed into the human world. The purest one among them was reincarnated as the son of the Prime Minister's wife.
However, this child has lived a difficult life since he was a child. His mother died in childbirth and his father ignored him. He had no choice but to climb over the wall and go out to live in the market. By chance, he met the traveling swordsman Li Changqing. Although he did not become a disciple, the Sword Master was willing to teach him swordsmanship and wisdom because of his righteousness and kindness. Ren Jiutian and Lan Xin, who have been together for many years, became close friends and worked together with Baili Chuge, the minister of Dali Temple, to solve the case. They uncovered the deep injustice of the Lan family and gradually became involved in the turmoil of the Three Realms.
As the adventure unfolds, Ren Jiutian recovers his lost soul and returns to the immortal position, with his power greatly increased. At this moment, the Three Gods summoned him to perform a mission concerning the fate of the Three Realms. Ren Jiutian's decision will profoundly change the future of the Three Realms.
