Priceless artifacts have been stolen from all over Europe by an International theft ring. Following the clues, Willard and Inspector Bufflehead go undercover in Texas and stake out The Alamo. Miss Mallard travels to Texas to vacation with Willard after he solves the case, but when she is thrown from her horse, Miss Mallard stumbles upon a mystery of her own. It soon becomes clear to Miss Mallard that she and Willard are working on the same case, and thanks to both their sleuthing, the International theft ring is brought to justice.