Thea Stilton and the Riddle of the Ruins (Thea Stilton #28)

The Thea Sisters participate on a dig at Hierapolis. During their visit to the excavation site, Professor Brenninger unearths a series of priceless and very old figurines. But the Thea Sisters soon figure out that it's a scam. They start to investigate and discover that the figurines are fake, exposing Professor Brenninger's plans.