Slim organizes a regiment to protect Snakeville against the Mexicans. Sophie, for whose hand Slim and Mustang Pete are rivals, induces Pete to join. Pete, although he dislikes the idea, enlists, and the way Slim puts him through the manual is uproariously laughable. Pete finally deserts, hides beneath the drill hall and fires two revolvers in such a way that Slim believes they are being attacked by the enemy. Slim tries to escape, but is caught and driven out of town on a mule. He finds the Mexicans hidden in a house, locks the door on them and when Pete, Sophie and the rest of the defenders arrive, he has the enemy's arms and is in command of the situation. Sophie falls into his arms and Slim is hailed as the conqueror.
—Moving Picture World synopsis