Truck drivers Steve Hackett and Bill Purvis are fired from their jobs with the West Coast Trucking company for not using second-gear going down steep grades. Davis, the company vice-president, surprisingly asks them to carry a load of merchandise to Arrowhead and offers a $1000 bonus. He tells them it is a load of lettuce. Several miles out of Los Angelese, they are stopped by a mob of lettuce-farm workers on strike. When the first crate is tossed off the truck, it explodes and the two pals learn their merchandise is a cargo of dynamite. The workers let them proceed and they crash into a car driven by Mary Stevens, whom they had met at a restaurant. She and her dog, "Butch" (played by a Credited dog named Stooge), join them and they deliver their cargo, and learn unscrupulous real-estate operators have jammed the locks on the dam in order to ruin the ranchers and farmers and take over their property.