Arthur and the gang learn about the importance of a balanced diet to overall health when Mr. Ratburn challenges the class to find the perfect food for surviving on a desert island and everyone picks junk food. When D.W. is finally told a secret, she quickly learns that getting a secret is easy, but keeping one is a lot harder than she thought. Francine is shocked to learn that, despite her conservation efforts, her water meter levels are twice as high as Arthur's. Arthur and D.W. are convinced that in Grandma Thora's attic they'll find treasures that will make them famous on TV.