Matt Helm is called out of retirement to stop the evil Big O organization who plan to explode an atomic bomb over Alamagordo, NM, and start WW III.

Taggart's family is slaughtered by a rival rancher. Taggart mortally wounds the rancher and kills his son. Before he dies the rancher hires three bounty hunters to avenge him with the promise of $5000 as a reward. Taggart must flee into Apache territory to escape the wrath of the trio of hired killers.