At the height of the frontier era, a train races through the Rocky Mountains on a classified mission to a remote army post. But one by one the passengers are being murdered, and their only hope is the mysterious John Deakin, who's being transported to face trial for murder.
A murderous thief on the run with stolen loot forces a poor rancher to guide him across the desert into Mexico. Accompanying them is the rancher's wife, who happens to be the killer's former girlfriend.
Marian Forbes has been having an affair with her boss and when he drops her for another woman. In an act of jealousy and greed she convinces an acquaintance to murder her former lover and then impersonate him just long enough to get their hands on a large sum of money.
