The film opens with two bandits breaking into a railroad telegraph office, where they force the operator at gunpoint to have a train stopped and to transmit orders for the engineer to fill the locomotive's tender at the station's water tank. They then knock the operator out and tie him up. As the train stops it is boarded by the bandits‍—‌now four. Two bandits enter an express car, kill a messenger and open a box of valuables with dynamite; the others kill the fireman and force the engineer to halt the train and disconnect the locomotive. The bandits then force the passengers off the train and rifle them for their belongings. One passenger tries to escape but is instantly shot down. Carrying their loot, the bandits escape in the locomotive, later stopping in a valley where their horses had been left.

Meanwhile, back in the telegraph office, the bound operator awakens, but he collapses again. His daughter arrives bringing him his meal and cuts him free, and restores him to consciousness by dousing him with water.

There is some comic relief at a dance hall, where an Eastern stranger is forced to dance while the locals fire at his feet. The door suddenly opens and the telegraph operator rushes in to tell them of the robbery. The men quickly form a posse, which overtakes the bandits, and in a final shootout kills them all and recovers the stolen mail.