Taking care of a baby dinosaur is hard work. And it's even harder when you can't tell anyone about him! Frank and Sam are good at feeding, cleaning, and walking Peanut. But their grandma has found a new fossil and it looks just like Peanut's horn...only a thousand times bigger! Will baby Peanut grow to be that huge, too? How do you hide a dinosaur when he becomes as big as a house? It won't be easy. Especially when scientists come to the dig site to make a movie about the new fossil.