When you're the best fighter around, you'd better be prepared to prove it! No sooner was a new security escort for the Imperial Governor chosen; then he was challenged to a duel and slain right before his family's eyes by a mysterious traveling swordsman known only as The Thunder Sword, who disappears and is never to be heard from again. Now orphaned, the former security escort's two children separate, and wander ancient China, developing their sword skills in the hopes of taking revenge against The Thunder Sword for killing their father. However, The Thunder Sword has secrets of his own, and will not be so easily found.