Set in the chaotic waning years of the Tang Dynasty, the drama revolves around a secretive assassin organization under the wings of a ruthless warlord. Political and personal ambitions clash as brotherhood is put to the test and court conspiracies weave dangerous fates for all the players caught in the dangerous game.
In the chaotic aftermath of the Tang Dynasty, China falls into a warlord era with Lee Hak Yung (Paul Chun) and Chu Wan (Lau Siu Ming) contending for the empire. Using the beauty of his daughter Wan Lo (Idy Chan) as bait, Lee attracts to his services thirteen top swordsmen of different martial arts sects, dubbed the "Thirteen Protectors". As the top swordsman of the organization, Chun Hau (Felix Wong) becomes Lee's most trusted assassin and wins Wan Lo's love. Ambitious fellow Protector Kwan Lei (Kent Tong), however, has significantly greater designs in mind, and he's determined to eliminate Chun Hau whom he sees as a threat to his position.