On a family vacation, Flat Stanley's younger brother, Arthur, feels put out that his half-inch-thick sibling can fold himself up to get comfy on the plane. Snorkeling together later, they discover a treasure chest on a sunken ship. Stanley takes a gold bar, which he loses while attempting to save a dolphin trapped in a net. When a storm comes up suddenly, Stanley makes himself surfboard-flat and lets Arthur ride him into shore. They return to the treasure cove with their parents to find that the ship has disappeared. That's a lot of plot for a 32-page I Can Read! book, but fans of the Flat Stanley series will enjoy the light tone of the story, while cartoonlike illustrations define the settings clearly. Though the story may be as thin as its hero, it will appeal to many.