Charlie and Sally, two ten-year-olds, live on adjacent farms on land that belongs to Longhowls, an ancient manor house that is home to exotic wild animals. They have long wished to be accepted into the summer holiday programme created by the owners of the manor house to give children the chance to get up close to the wild animals, and to learn about the history of Longhowls itself. Finally accepted into the programme and jumping with excitement, Charlie and Sally get ready for adventures with the wild animals, and the much wilder occupants of Longhowls. When they find ancient Roman treasure, it becomes clear that some of people around them have hidden agendas, and they get drawn into the dangerous and murky world of antiquities smuggling.