While traveling by train to Denver, Matt Rockford meets and falls in love with Lisa Caldwell, a beautiful woman who, unbeknownst to him, has been falsely accused of murder. Lisa is blackmailed into losing five thousand dollars in a poker game to a U.S. Marshal as a bribe to free a notorious outlaw and his gang. When the prisoners escape and the train is snowbound, Matt, Lisa and their fellow passengers find themselves in deadly peril.