Duke and Annie are puppies in Scrappy-Doo's old gang from his old neighborhood in New York City.
Annie still lives in the old apartment building.
Duke lives in carboard box outside at the front. Duke is an expert at getting to places around New York.
Duke is a small tan terrier with black spots on his back. He wears a red collar with a red triangle-shaped dog tag.
Annie is an old english sheepdog with hair covering her eyes, making it hard for her to see anything. She wears a black necklace with a pink heart-shaped dog tag.
They are both the only ones who seem to enjoy Scrappy's Secret Whistle (Scrappy whistles in a high-pitched sound which is so loud, everyone had to cover their ears, and it cracked the glass and blew out the tires on the Mystery Machine).