As dawn broke over the Sonora Desert, in May of 1681, only a few cumulus clouds left from an early morning rain shower hovered in the pale blue sky over the distant mountains. a caravan of over-burdened ox carts carrying a load of silver and gold ore destined for a Spanish smelter on the coast of the Gulf of Mexico. In the already hot sun, the drovers are praying they will reach the next water hole before sun set. Over eighty mounted conquistadores' wearing metal body armor rode to the left and right of the caravan which included one hundred and fifty-two bound Yaqui slaves, another contingent of conquistadores followed behind on foot. Unknown to any of the Spaniards, they were being watched by vengeful Yaqui warriors seeking to massacre all conquistadores. The caravan was unknowingly being led into a trap.
Two hundred years later a lone American treasure hunter attempts to find the lost silver and gold ore stolen from the conquistadores only to be kidnapped by a notorious Mexican outlaw and held for ransom. Two U.S. marshals are joined by a team of Mexican law officers in an attempt to free the treasure hunter, chasing the outlaw across northern Mexico in an attempt to extract justice.