Dee Dee is thrilled when her mother asks her to go into Dexter's room and check to make sure he's ready for school...because it means she can sneak into his secret lab and wreck everything in site. This time, Dee Dee gets her hands on Dexter's newest invention: a hand-held device that turns her and her brother into various animals (from a rabbit, to a frog, a hamster, a tiger, even a whale) as they try to hide what's going on from their mom and get ready for school at the same time.