A modern young woman transmigrates into Jiang Heng, a girl with half sea-demon blood. Carrying the deep-seated grudge of the sea-demon royal family, which was brutally wiped out, she descends the mountain to gain experience. Her contracted companion, a metal-eating beast, harbors the resentment of an ancient race within its body and can switch between the forms of an ancient battle beast and an adorable panda. She encounters Sheng Wujin, a genius swordsman from the Beidou Sword Sect. The two bicker like a pair of quarrelsome rivals, constantly trading barbs and setting traps for each other, yet always having each other's backs when danger strikes. Following clues about evil cultivators causing havoc across the land, they gradually unravel the mysteries and join forces to fight various wicked cultivators. After surviving numerous life-and-death battles, they gather evidence of the crimes committed by the Qishi Heavenly Sect, painstakingly uncover the truth about the past that has been buried, and vow to expose a shocking conspiracy hidden for many years.