One day, while playing in Washington Square Park in Greenwich Village, David and Leilah are thrilled to discover a real wizard living behind the little black door in Washington Square Arch. Alas, he is only a second-class wizard, he tells them, and sometimes he has trouble with his spells. So when the Wizard accidentally turns David's Scottish terrier, D. Dog, into a statue and the statue is stolen by Mr. Pickwell, a nasty antiques dealer, it's up to David and Leilah to get D. Dog back--before Mr. Pickwell sells him!