When things go missing from neighbors in their Alpine town, the triplets have a mystery to solve in the fourth book in the Trillium Sisters series perfect for fans of Mia Mayhem and The Wish Fairy. Emmy has been helping her veterinarian dad create an underground Paw Park for all the pets in Trillsville. When it's cold -- or hot -- the animals can all play in a safe, natural space. On the grand opening of the park, the girls learn from their clients that odd things have gone missing from their homes: lightbulbs, trash can lids. The girls really want to help their neighbors. But they have to watch the pets in the Paw Park, too. Their search for the burglar leads the sisters to a deep dark mysterious spot in the forest -- that leaves everyone in danger!