Overworked office worker Lin Bei dies suddenly after staying up all night and transmigrates into a golden arowana belonging to a female livestreamer. He binds himself to a Devouring Evolution System with the ultimate goal of becoming a dragon. When a fire breaks out in the house, he saves himself by spitting water. After devouring a golden python, he unlocks the bloodline of the Divine Dragon. His extraordinary abilities during a livestream attract a research institute, which offers a huge sum to buy him. To avoid being dissected, he escapes through a toilet and enters a reservoir. Fed by enthusiastic anglers, he evolves at an astonishing speed and subdues a mutated snakehead fish as his subordinate. Later, he slays a rampaging mutated alligator snapping turtle and is taken under the protection and care of the 749 Bureau. At the government's request, he heads to the Yangtze River to eliminate a gigantic mutated catfish. Just then, spiritual energy begins to revive across the world. Lin Bei breaks through his bloodline limitations and transforms into a flood dragon, while mutated beasts and awakened humans emerge one after another, plunging the entire world into crisis.