At age nine, their trait of feeling pain from the other's injuries becomes apparent (it becomes the film's predominant running gag); they accidentally burn down their house while playing with this power, and they decide to split up.

At age 30, they reunite: Louis (now Luís) wound up in Mexico working low-end jobs (though he claims to be a wealthy businessman) and Lucien, who stayed in France, has grown resentful of the royals' harsh treatment of peasants in the country, particularly that of the queen's regent, the sadistic (in more ways than one) Fuckaire, who usurped the king after his disappearance.

The cowardly Luís is reluctant to help his brother's revolutionary plans, but both find themselves drawn to two of the queen's daughters (played by Cheech and Chong's real-life wives).

The crux of Lucien's scheme is to disguise themselves respectively as a gay Spaniard hairdresser and Nostradamus, who are prepared to visit the queen with the Marquis du Hickey.

After their saga concludes, Los Guys resume playing in an outdoor cafe, covering Chuck Berry's "Nadine," to an indifferent audience.