In the late 1800's, Sicilians Franco and Ciccio are serving 20 years of prison for stealing two mules, when they are helped to escape by an American who says he is a friend of their grandfathers, who were killed in Texas by a gang of bandits who wanted to take over their gold mine. The two friends travel to America to take posses of the gold mine, but they soon discover that they are not the only ones who want it.
Two brothers, Bull and Jonathan Bullivan, witness the murder of bandit Black Boy who had been terrorizing Golden City. The bandit had been put in place by the city mayor, who wants the local residents to leave so that he can keep their land, where there is oil. The two brothers eat a chicken that has been fed with a strong tonic and they become sort of invincible for a few minutes. The mayor, pressured by the villagers, appoints the Bullivan Brothers as sheriffs and tasks them with the arrest of Black Boy.
Zenobia, Queen of Palmira, revolts against Rome and defeats the Roman troops, but she makes a big mistake when she falls in love with enemy officer Marco Valerio.