Two tramps hold up small-town Ferndale's railway station night operator Helen, lock her in a closet, and escape. Later, standing on a bridge over the freight yards, Helen sees the two bandits aboard an outgoing freight and drops onto the roof of the car from above as it crosses underneath. A chase along the roofs of the speeding cars ensues.
Helen is captured by two yeggmen who throw her into a refrigerator car; finding a meat hook, she chops her way into the ice chamber and reaches the top of the train in time to avert a collision of two trains.
Helen, informed of the danger which menaces an excursion train because another engine on the same track is running wild, mounts a motorcycle and speeds down the track to warn the passengers of their imminent peril. Nearing a river trestle under repair, she hurtles into the river; undaunted, she swims to the opposite bank and flags down the excursion train in the nick of time, causing the engineer to run his train onto a siding just a few moments before the runaway dashes by.
