"Johnny" (John Wayne) and his patient colleague "Pop" (James Gleason) are employed in contract mining, constructing a tunnel for railway magnate "Alexander" (Sir Cedric Hardwicke). Alexander proves to be an abrasive character, and disagreements about safety measures and expenses arise early on. Things become complicated when "Johnny" meets Alexander’s daughter, “Maura” (Laraine Day). Her father strongly objects to th…