A book that takes into account what beginning readers need--simple words, uncomplicated sentence structure--but provides little original in the way of plotting and action to keep them involved. In a sequel to The Biggest Pest on Eighth Avenue (1997, not reviewed), Mary Lou and her friends are sure that Leroy, an adult who has the reputation of having once been a really bad kid, is hiding stolen money in his backyard. So they set about finding clues. They sneak into his house and find various mysterious objects, but everything is explained when they meet Leroy, now a fire marshal who trains tracking dogs. The formula is too familiar; new readers will already have encountered similar events in such picture books as Roni Schotter's Captain Snap and the Children of Vinegar Lane (1993).