Based on

Movies like Two-Gun Gussie (1918)

A mild-mannered young man has left home, and is now playing the piano in a bar in the west. The dangerous criminal Dagger-Tooth Dan enters the bar where the young man is playing. Soon afterwards, the local sheriff also arrives, with some letters that he has received. Dan notices the letters, and he switches the information in them to make the sheriff think that the piano player is the dangerous one.