The Three Mesquiteers—Stony Brooke, Tucson Smith, and Lullaby Joslin—are headed back to Texas aboard a paddle steamer when a tense blackjack game erupts into violence. Pierce Talbot is caught cheating, draws a knife on his opponent, and is stabbed with his own blade, tumbling overboard. Ashore, Talbot runs into a crafty counterfeiter named Hazleton, who has fraudulently filed a land title for a staggering 13 million acres in the name of Don Luis de Serrano. Talbot impersonates de Serrano, with Hazleton’s ally Soledad posing as his wife, and after a careful inquiry the court declares the claim genuine.
A cloud of fear hangs over the ranchers, who worry that de Serrano will seize their land. In reality, he imposes a brutal rent of $1 per acre, a rate many ranchers cannot bear. Enforcers are sent to collect, cattle are threatened with forfeiture, and the stakes rise as the land itself seems to slip from the ranchers’ grasp. When collectors press the Mesquiteers’ own ranch for payment, a gunfight erupts. Outnumbered and short on ammo, the Mesquiteers pull off a clever ruse, disarming their pursuers, and the sheriff steps in, ordering them to leave unless they can pay. They comply, but not before stepping in to aid Susan Randall and her young brother Tim, helping them dodge a crippling tax on the cattle they’re moving by knocking out the two officials.
With the sheriff’s permission at best and the President seemingly unable to intervene, the Mesquiteers turn to more clandestine justice. They adopt disguises and become known as Los Capaqueros, secretly redistributing money to ranchers so taxes can be paid. Hazleton and de Serrano set a trap by targeting the next ranch due for tax, but Los Capaqueros elude capture and retreat to town. A near-miss in a stable followed by a stealthy intrusion into a bedroom forces a dramatic reveal: Stony recognizes de Serrano as Talbot, exposing the scar that proves the counterfeit plan is unraveling.
Tim, worried for Susan, urges her to seek Captain Beckett on the steamer and to relay what she knows to President Garfield. Having unearthed solid evidence, Susan dispatches a telegram to the President, but tragedy interrupts— Garfield is shot just as it arrives. The Mesquiteers are taken before a firing squad, only to learn that the shot was blank and that the town’s mob still believes in their innocence. When a mob storms de Serrano’s hacienda, the Mesquiteers slip in through the back, capture Talbot, Hazleton, and Soledad, and force Talbot to sign a confession rather than reveal the truth to the mob. Hazleton finally admits his crimes, and with the confession in hand, the trio tells the mob the full story and returns to their ranch, their resolve strengthened by the evidence of a conspiracy thwarted and justice briefly served.
