Ten years ago, eight-year-old Xiao Jin witnessed her entire family being murdered by the three great villains of the martial world. She only survived by being hidden in a cabinet by her mother. After escaping, she was rescued by the reigning prince, Dongfang Yin, who adopted her as his daughter. She changed her surname to Dongfang and became a princess. Ten years later, Xiao Jin's swordsmanship is unparalleled. She becomes a sharp blade for Dongfang Yin in his struggle for power at court. At the same time, her superb sword skills make her the mysterious Sword Immortal, Yuan, in the martial world. Before helping Dongfang Yin seize the throne, Xiao Jin asks to settle the score for the Xiao family's massacre a decade ago. She bids farewell to Dongfang Yin and travels to Jiangzhou to investigate the truth behind the tragic annihilation of her family.