Dick Lazarus and his gang are feared on both sides of the Rio Grande. Lazarus's increasingly daring crimes see him raid the ranchero of the Robles family in Mexico, stealing a herd of horses and taking a hostage - Luis Robles - who should fetch a hefty ransom. Dan Calloway, owner of the stolen herd and Luis's friend, is determined to rescue Luis and regain his possessions. Ignoring the warnings, and with an unexpected ally on his side, he pursues Lazarus across the Rio Grande, and along the Tonto Rim...