Su Yun, an overworked office worker, unexpectedly transmigrates into the body of a massive yellow ox used by a farmer to plow fields. Just as he opens his eyes, villagers nearly slaughter him. At the critical moment, an evolution system binds itself to him, allowing him to escape into the perilous Forest of Ten Thousand Demons. By devouring plants and demon beasts, he accumulates evolution points and continuously transforms, eventually befriending a young boy named Li Bufan. Together, they head for the Ten Thousand Beasts Sect of the human race. The sect enslaves demonkind through beast-taming techniques. To save Li Bufan from abuse, Su Yun wreaks havoc throughout the sect. From an ordinary farm ox, he evolves into a Golden Ox Mystical Beast, breaks free from his shackles, and vows to shatter humanity's control over beasts and dominate the entire territory of the Ten Thousand Demons.