Julie Malloy and her friends make a school visit to the museum. On leaving and reclaiming her bag from the checkout, she is given the wrong one. Nobody claims it and her own is still there. When they are able to open the bag, they find a map indicating something hidden. As they unravel the mystery, they find themselves in a dangerous situation with a gang of criminals who export Australian wildlife overseas. They must draw on all their courage and intelligence to solve the mystery and keep themselves safe.