Arrested for speeding by highway patrolman Bill Rolph (Robert Paige), J.W. Brady (Robert Middlemass), the president of an oil refinery, offers him the assignment to find the culprits who have wrecked his gas stations, hi-jacked his trucks and attempted to blow up his plant. Bill, having previously handed a summons to Brady's daughter, Jane (Jacqueline Wells), accepts the offer. He discovers the refinery police chief is working against his employer, and also captures a dynamiter on the grounds. Jane inadvertently exposes him to Walter Brennan (Arthur Loft), the general manager also working against Brady. Bill is made police chief of the refinery. Jane, unable to enter the plant, under Bill's new regulation, determines to spite Bill when she finds one of the company's trucks, driverless, on a hill. Unaware that the truck is loaded with explosives intended to blow up the plant,she starts it down the hill, planning to bust through the gate, but loses control and is knocked unconscious. Bill speeds to the runaway truck on his motorcycle, and snatches Jane to safety just before the truck smashes into a wall and explodes. Brennan employs an aviator to bomb the plant that night. Bill removes the captured dynamiter to the control house and substitutes a dummy. Brennan comes in, fearful the captured man will talk, and riddles the dummy with bullets.