Cosette's dream comes true when she rescues Oreo from the animal shelter. Now she has a little dog to play with and love.

But messes keep happening in their home-overturned trash cans, half-eaten cakes, and spilled flour bags. Cosette's mom is sure Oreo is the one creating all the trouble. Mom threatens to send him back to the shelter if Cosette can't make him behave.

Cosette knows Oreo is a good dog. He wouldn't have made any of those messes. She'll need to use all her detective skills to find the real troublemakers and save Oreo.

A fun book about the special relationship between a child and their pet and how together they solve the mystery. Includes two amateur detective activities using items found in the home: dusting for fingerprints and writing in invisible ink.