The forty man patrol of U. S. Dragoons rode into Mexico, their mission the capture of Santa Ana's treasure horde, their leader Lieutenant Boyd Reagan. Reagan had been in Mexico before. He knew the country like the palm of his hand. He spoke the language, ate the foods. He had a fiercely patriotic sweetheart. All Reagan had to do was capture the treasure, and then get it, his girl, and his tiny command out of the heart of a hostile country - where even his own men were enemies!