Set in the mystical realm of the Demon Cultivation Sea, the film follows Wang Lin, a determined cultivator, as he confronts the sudden emergence of the Eternal Night Demon City. This dark force threatens the surrounding sects, including the Yun Tian Sect, home to his beloved Li Muwan. When Li Muwan is poisoned during a fierce battle, Wang Lin embarks on a perilous quest to obtain the antidote, facing formidable adversaries and uncovering a conspiracy that spans a millennium. Their journey culminates in a climactic battle against the Demon Lord, testing their strength, trust, and love.