When Don is told he can't dig any more holes around the nest, he complains that he needs his own day just for digging holes-a hole-iday! The kids make up an imaginary holiday just for Don and recruit the Oryctodromeus to help dig all the holes Don could ever hope for. / The Pteranodon kids meet a new, small mammal friend, Adele Alphadon, and introduce her and their Big Pond friend, Cindy Cimolestes, to a new concept -- that not all Mesozoic creatures are dinosaurs. And that includes the Pteranodons! They live in a diverse world.