Ed and Charlie Whittle often escape their abusive life at home by going for walks along the railway tracks which pass through their small town. On one such trek the brothers come upon a remote railway siding where they find an abandoned locomotive coupled to a small passenger car. To their surprise they learn that a former railway man, Jim Smith, has been working to restore the engine. Jim invites the boys to travel the country with him in exchange for their help fixing up the train, so they decide to take him up on the offer and run away from home. Once the locomotive is deemed operational, the crew start a new shipping business and set out to fulfill a number of delivery contracts North of their town.
Shortly after their departure Jim and the boys are joined by two additional men, Sully and Lamont, but it's not long before things start to turn sour for Ed and Charlie, as it quickly becomes evident that the other members of the crew openly resent their presence on the train and start to make their lives miserable. It isn't until the boys discover that the men are actually planning to rob of a remote gold mine that they begin to fear for their very lives. Ed and Charlie aren't sure who to trust or how they might escape their perilous situation, so they're both forced to put all of their creative energies to work in order to make it off the train alive.