Cattle rustlers were hitting the spreads of the biggest Texas ranchers. They were striking the most vulnerable ranches, those along the Rio, and running the cattle into Mexico. Even the cavalry couldn't stop them.
The Texas and Southwestern Stock Raiser's Association hired Fargo to put a stop to the rustling once and for all. They offered him $30,000 to go into Mexico and bust off the ring of thieves. Fargo took on the job for the money but something else entered the picture—the beautiful widow whose husband had been killed.