When a murderous Ronin named Thunder Sword wanders into a Chinese city, challenges the newly appointed royal bodyguard to a public duel, and then brutally slays the man in front of his two children before vanishing into this air, he sows the seeds of his own demise in this action-packed martial arts classic. In the years that follow, the vengeful children train night and day with hopes that they will one day be able to locate their fathers killer and make him pay for his crime.