 Truck driver Buzz Larkin gets clearance to leave his truck parked overnight on the grounds of the Jarmin Manufacturing Company. During the night, his older brother Whitey and their accomplice Jim emerge from crates on the truck. They assault the watchman, rob the safe of $27,000, and return to their hiding crates in time for the foreman (and Dan Mathews) to permit Buzz to leave the grounds with the truck. Subsequently, Dan learns that Whitey was a convicted safe-cracker and he deduces that the Larkins and their accomplice are the perpetrators. When Dan and his officers arrive at the Larkins  home, Whitey becomes anxious to avoid a return to prison and initiates an armed conflict.