The modern protagonist Lu Xuan travels through time into the world of Journey to the West and is reborn as a weak snake demon under the command of the Chaos Demon King. After witnessing Sun Wukong's birth with his own eyes, he realizes that the great calamity of Journey to the West is about to begin and that low-ranking demons are doomed to die. At a critical moment, he activates the Demon Race Evolution System. By exchanging resources and surviving tribulations, he continuously evolves. Eventually, he can no longer remain hidden and becomes a powerful Demon King, challenging Heaven and Earth and shaking the Three Realms with his might.