The ancient demon king Wen Ji was betrayed by his cronies and surrounded by the fairy world. He used his own demon essence as a guide to sleep under the cold pool of the Valley of Ten Thousand Demons. He slept for a thousand years. Thousands of years later, Su Qinghuan, a human girl, strayed into the cold pool in search of medicinal herbs and accidentally awakened the sleeping demon king. After waking up, Wen Ji's demon power was greatly damaged and his memory was incomplete. He was only obsessed with the word "betrayal". He mistook Su Qinghuan for the reincarnation of his betrayer, but as they got along with her, her purity and warmth gradually melted his frozen heart.
At the same time, the forces in the fairy world that had been encircling Wenji back then noticed his awakening and set out to kill him again. There were also people in the Valley of Ten Thousand Demons who coveted the position of the Demon Lord and secretly sow discord. While Wen Ji was looking for a way to restore her demon power and piece together her lost memories, she was protecting Su Qinghuan from being hunted by the Three Realms. However, when she uncovered the truth of the millennium, she discovered that the betrayal was actually a conspiracy against the Three Realms, and Su Qinghuan's identity was far more complicated than "reincarnation." When the conspiracy surfaced and the Three Realms faced the crisis of overthrowing, Wen Ji had to make a choice between "revenge" and "protection", and his relationship with Su Qinghuan will eventually illuminate the millennium fog in the test of blood and fire.
