When Murray Sinclair (Robert Preston) gets fired from the railroad he seeks revenge and begins to wreck trains and joins up with Barney Rebstock to commit the crimes. (Donald Crisp). His friend and railroad detective, Luke Smith (Alan Ladd) has the task to track him down and stop him in order to save the railroad. To complicate things even more, Smith has a real interest in Murray’s beautiful wife (Brenda Marshall) and the feeling is mutual. How will Luke handle the conflicts that face him? Will he be true to his duty or will his friendship win out over common sense and the love of a woman?