It's volunteer week at Carl Sandburg Elementary School, and Nancy is very excited about her job. She will be walking Mrs. Rutledge's dog, Baby. Mrs. Rutledge owns the biggest, fanciest house in River Heights. And she also owns the smallest one—a beautiful antique dollhouse.

Nancy loves the tiny furniture and little windows of the dollhouse almost as much as she loves walking Baby. But one day, five pieces of doll furniture are missing, and Mrs. Rutledge thinks Nancy took them! But Nancy is a detective, not a thief...right? Nancy must use her very best detective skills to get herself out of trouble!