Where is the Secret City?When Paulina gets a phone call from home telling her that a friend is missing the Thea Sisters travel to Peru to help solve the mystery. There, the five mice climb the Andes Mountains in search of a missing archaeologist. Along the way, they stumble upon clues leading them to a mysterious hidden city. Will the Thea Sisters find Paulina's friend - and the treasure of the Secret City?Meet the Thea Sisters!Nicky is always in a good mood when she's outdoors.Colette is energetic and full of great ideas.Pamela is a peacemaker who can't stand arguments.Paulina loves travelling and helping other rodents.Violet is detail-oriented and always open to new things.