Legend has it that hundreds of years ago, the world was plagued by a scourge - a giant snake with nine heads and a golden body. Often transforming into a woman as beautiful as a celestial fairy, Hydra wreaked havoc on the world and called herself Lady Golden Snake. People were terrified until Master Nan Hua appeared. He defeated the Hydra, beheaded her, and trapped her immortal spirit in a divine sword. Hundreds of years later, a mysterious demon broke into the DemonSlayer's Hall, where the sword with the Golden Snake's spirit was kept, and stole the sacred relic. Qu Ling was tasked with retrieving the sword, but due to her weak spiritual power, she could not resist the Golden Serpent and decided to seek the help of Bian Xiao Ya, a demon hunter. Together they embark on a journey to retrieve the divine sword and save the world from the Hydra's second coming.