An ordinary snake named Xu Hei accidentally swallows a "human pill," awakening his intelligence and gaining the magical treasure Demon God Cauldron. He cultivates the Nine Transformations of the True Dragon, cautiously growing stronger until he becomes the Snake King. After leaving the mountains, he is drawn into conflicts among cultivation sects and uses his wits to turn the tables on powerful enemies and establish his own forces. Surviving nine life-and-death trials, including lightning tribulations and heart-demon tribulations, he sheds his serpentine form and approaches the form of a dragon, unifying the snake tribes and earning the title Ancestor of Snakes. He defeats the Snake-Catching Alliance, his thousand-year-old enemy, breaks through the barriers of the immortal realm, and ascends with his trusted followers, completing his rise from an ordinary snake to a true dragon immortal.