The Mystery of Metropolisville centers on a tragic boating accident on "Diamond Lake" in "Metropolisville," which lies near the "Big Gun River" in "Wheat County." The plot is populated with various Western types, such as a seedy land speculator named Mr. Plausaby, his beautiful step-daughter Katy, a college student from back east who falls in love with Katy, Whiskey Jim the stage-coach driver, and a displaced Hoosier poet in a sod cabin.