Billy Wayne, railroad detective, is ordered to run down a gang of freight car thieves. In one of the rifled cars he finds a piece of paper on which several Italian words are written. He is led to suspect a gang of section hands working in the vicinity and fixes upon an Italian called Nick as their leader. Billy saves the life of Tony, a laborer. Nick, who loves Rosa, Tony's daughter, resents this friendship and quarrels with Tony. That evening the latter receives a threatening missive and in alarm sends Rosa for Billy. The detective finds that the writing in the letter is identical with that on the paper in his possession. The following day Billy accidentally loses a pair of handcuffs, which are found by Nick. The detective is waylaid that evening and is placed in a sack. Noticing a mall pouch hanging from a crane, and waiting to be picked up by the fast mail, Nick removes the pouch, replacing it with the sack containing Billy. The gang then proceeds to Tony's house. They attack him, after informing the man of the fate in store for his friend. Rosa dashes out of the house to save Billy, but the whistle of the fast mail tells her she cannot reach the crane in time. In desperation she snatches a stiletto from her bosom and hurls it into the mail car as it dashes by. The knife strikes the clerk, who is holding the mail catcher, in the arm. He releases his hold just in time to miss the sack containing Billy. The train is stopped and Billy liberated. The passengers, headed by Billy, rush to the house in time to save Tony. The desperadoes are soon in custody, and as Nick is taken away, Billy asks Rosa to be his wife.
—Moving Picture World synopsis