On a trip to Los Angeles, Tex Wilson, who owns the largest ranch on the Rio Grande, brings a runaway horse under control, whereupon its rider, Roberta Stephens, invites him to a reception at the home of her father, Col. Stephens. Dressed in his cowboy togs, Tex is mortified to discover the other guests attired in evening dress, but when one of them dares to laugh at him, he forces the rude guest to exchange clothing with him. Eager to aid the government in its war effort, Tex invites the colonel, a government purchasing agent, to inspect the horses on his ranch, and just before the colonel and his daughter arrive, Tex orders the horrified cowboys to don evening suits. During the party, a group of riders employed by the German government raids the ranch, abducting Roberta. Tex pursues them across the border, and after a series of narrow escapes, he succeeds in rescuing Roberta and putting the raiders to flight.