Steve McLain (Johnny Mack Brown), an undercover agent for the express company, uncovers a gang of robbers, led by Ace Pringle (Ted Adams), hiding behind the badges of law officers.

In "Undercover Man", Steve McLain (Johnny Mack Brown), an easy-going harmonica-playing undercover agent for the express company, uncovers a gang of stagecoach robbers, led by Ace Pringle (Ted Adams), hiding behind the his stature as a town leader, and an easily-influenced and dumb Sheriff (Horace Murphy.—Les Adams <[email protected]>

Ace Pringle is after the strongbox on the stage. When he sends his men after it, Steve McLain an undercover agent breaks it up. Now thinking Steve is after the box, Ace unsuccessfully tries to have his men and his stooge Sheriff kill Steve. Steve takes the box before Ace's men can get it and hides it but his girlfriend sees him. Thinking Steve an outlaw she tries to return it but is spotted by Ace and his men who grab the box and flee.—Maurice VanAuken <[email protected]>