The Swills, on yet another usual rampage, steal dowry money from some mail order brides; Brisco and Bowler save them from their runaway wagon (where they have been trussed up by the Swills). To cap their crime, the Swills intend to steal "El Magnifico Quinto", a prize bull sent as a gift from Madrid Spain to its sister city, Madrid, CA. (The citizens in California had originally intended to celebrate the bull's arrival by eating it.) If anything happens to the bull, it could be a diplomatic gaffe. (Socrates frets away in Madrid, California - assigned as liaison for the transfer of the gift.)
Before they can try to steal the bull, Brisco and Bowler encounter the Swills in a bar in "Preacher's Head", and a merry barfight ensues, during which Brisco accidently slugs the sheriff. The Swills escape - Brisco and Bowler wind up in jail, to be bailed out by the mail-order brides, who hope Brisco and Bowler can capture the Swills and get their dowries back. Reluctantly, the bounty hunters agree to take the women along as part of the deal.
The Swills head back to the old homestead, where their plan to steal "El Magnifico" and sell it to cattle ranchers is adjusted by Lil Swill to ransom the bull (a more workable plan). Brisco and Bowler arrive soon after the brothers leave the Casa Swill, to be nearly killed by the Swill kin, escaping just barely.
The Swills arrive in Madrid, followed closely by Brisco and Bowler (to the surprise of Poole), and capture the bull (and one of the brides as a hostage), but are trapped in the bull's barn. The Swills and Brisco bargain, during which Brisco frees the bull, saves the girl, and sets the Swills to flight.