Gideon Coppersmith can't find a missing ranchhand and pony before a mob lynches him. Now someone has come to take vengence.

As collateral for a loan, Texas cowboy Jim Barre is given a Mexican saddle. When the saddle owner is killed, his sister points an accusing finger at Barre. For Barre it is the start of an adventure involving badmen, a silver mine, and his accuser's love.

Lady gambler Mari Marshay decides to give it all up after a gunfight at her poker table kills a man. Leaving a note for the sheriff to locate the man's widow and return the deed to his ranch which was among her winnings, she boards the train called The Prairie Queen. Sheriff Milam has an urgent reason to catch up with Mari: the man has left a four-year-old orphan. But circumstances on that train are heading towards catastrophe. Eventually the train...