本片改编自武侠故事，讲述了一位日本挑战者在宫廷阴谋与武林门派纷争的背景下，寻访中国传奇剑客的历程。这位年轻剑客（谢霆锋饰）此行只为完成师父临终前的遗愿——寻回中原失传已久的九柄绝世名剑……
A young swordsman (played by Nicholas Tse) travels from Penglai in the north to the Central Plains, wielding the renowned sword "Changguang" to fulfill his late master's dying wish: to locate the nine legendary swords left behind by ancient masters. Meanwhile, Bai Sankong (played by Ji Chunhua)—the leader of the Shandong martial arts alliance and a master of the Qingping sword style—has already pledged allegiance to the imperial court; he stages his own death during a duel with the young swordsman, effectively becoming a covert agent for the court within the martial arts world. Bai Sankong's grandson, Fang Baoyu (played by Qiao Zhenyu), was forbidden by his grandfather from practicing martial arts since childhood; however, driven by a vow to avenge his grandfather by killing the Penglai swordsman—and a desire to uphold justice in the martial arts community—he begins training under the "World's Greatest Swordsman," Ziyi Hou (played by Patrick Tam). Amidst life-and-death struggles, the Penglai swordsman meets and falls for Zhu'er (played by Gillian Chung), the daughter of the "Mad Knight of the Yellow River," Wang Dian, while Fang Baoyu becomes deeply enamored with Ben Yue (played by Yang Rui), the adopted daughter of Ziyi Hou. Eventually, the true identity of Mu Lang Shen Jun (played by Zhao Hongfei)—the young master of Qingmu Fortress—as an agent of the imperial Jinyiwei (secret police) is exposed, fully revealing the court's scheme to control the martial arts world and seize the treasure of the ancient city of Luoya.
A catastrophe is engulfing the martial arts world, and everyone's true allegiances are revealed. Amidst the turmoil, the Penglai Swordsman and Baoyu discover they are actually half-brothers sharing the same mother; they decide to join forces against the formidable Lord Mulang. However, just as Lord Mulang—who has mastered the peerless "Hunyuan Divine Skill"—stands on the verge of victory, he is slain by the sword of his beloved Princess Tuochen (played by Annie Yi), bringing the conflict to an end.
