Old friends Billy Carson and Fuzzy Jones ride into the town of King City to exact revenge on Dave Carr, the man they hold responsible for the murder of their parents years earlier. At his office, Fuzzy and Billy accuse Carr of being Andrew Carberry and leading their parents into a murderous trap after stealing their land claims. When Carr pulls out his gun and lunges for Billy, the weapon fires, killing Carr. As one of Carr's henchmen hastens to summon Marshal Baker, Billy and Fuzzy search the office and find a strongbox stuffed with unrecorded deeds made out to King Brett, the man who owns the town as well as the marshal. After slipping out the back door, Fuzzy and Billy proceed to Brett's office. Exhibiting the unrecorded deeds, Billy demands that Brett return the stolen lands. When Brett pulls his gun, Billy shoots him and soon after, Baker appears to arrest Billy and Fuzzy. Before Baker is able to take them into custody, however, U.S. Marshal Riley arrives to take charge. Riley has been contacted by Billy's employer, rancher Dan Stuart, to investigae the situation at King City. Claiming that he can prove charges of murder and robbery against Carr and Brett, Billy recalls a time twenty years earlier: Billy's and Fuzzy's families are traveling West by wagon train to file their land claims at Apache Mesa. Plagued by delays, the settlers are in danger of missing the filing deadline when Carberry, an attorney traveling with the wagons, proposes that the settlers give him their deeds so that he can ride ahead and record the claims. After the trusting settlers hand Carberry their deeds, he rides to meet his accomplice, Brett, and gives the signal to attack the wagons. Only Fuzzy and Billy survive the assault, and the boys are separated after being adopted by two different families. Billy continues that after twenty years, he met Fuzzy by accident in King City. Billy had come on behalf of his employer to protest the toll levied by Brett for allowing cattle to cross his land, and Fuzzy was in town peddling new and improved bullets. After Billy defends Fuzzy from an irate customer, Fuzzy recognizes Billy as his childhood friend. Impressed by Fuzzy's facility with explosives, Brett offers him a job, but Fuzzy refuses, and Brett then orders his henchman, Burke, to annhilate both Fuzzy and Billy. Overhearing their conversation, Helen Miller, Brett's secretary, warns Fuzzy and Billy of their peril. As Billy and Fuzzy ride to the Stuart ranch, Burke and his gang wait in ambush and open fire. While riding in the hills, Helen witnesses the attack and comes to their aid. After Fuzzy drives off their assailants with a well-aimed blast of explosive gel, Helen cryptically advises the pair that working for Brett will allow them to solve the mystery of Apache Mesa. At the Stuart ranch, Fuzzy and Billy muse about how Helen knows about Apache Mesa and enlist Stuart's help in their battle. Soon after, one of Brett's men approaches the pair and details a plan to use Fuzzy's explosives to blow up Stuart's water supply, thus forcing the rancher out of business. Rendezvousing with the gang at Stuart's well, Fuzzy and Billy recklessly handle the explosives, thus terrifying the outlaws into retreating to a nearby shack. After hurling explosives at the shack, Billy and Fuzzy force the outlaws into surrender. When Burke boasts that Carr will make a fool of them in court, Billy and Fuzzy realize that Carr must be the man for whom they are looking. Returning to the present, Billy asserts that the stolen deeds will corroborate his story. Satisfied with the evidence, Riley arrests Baker, and Helen then confides that her elder sister was one of those killed on the ill-fated wagon train.
