Gun Frontier is a forbidding and desolate terrain that permits no place for the feeble to aspire. Yet, it is a revered expanse for authentic men, as nowhere else does one feel more invigorated. Sea Pirate Captain Harlock and the nomadic samurai, Tochiro, dock on the Western Frontier of the United States. Accompanied by a cryptic woman they encounter en route, the duo confronts prostitution rings, bandits, and dishonest lawmen. Their quest leads them to search for a vanished congregation of Japanese immigrants, propelling them to scour the Gun Frontier from one end to the other.