It"s November, and the younger siblings of the A to Z Mysteries detectives have a new mystery to solve. ""The twins" new neighbors are up to something! It"s Thanksgiving, and a mysterious couple has moved in next door. Bradley, Brian, Nate, and Lucy must work out the clues: The neighbors have built a tall wooden fence. They"ve bought some strange parts for making . . . something. They"ve even put up a suspicious tent in their backyard, with a big, scary dog to guard it. What could they possibly be hiding?