When Jamie moves to Dinosaur Cove with his father he's looking forward to doing some fossil hunting on the beach. But when he and his friend, Tom, discover a forgotten cave with fossilised dinosaur footprints, it takes them to another world . . . a world of dinosaurs. Jamie and Tom discover some fresh dinosaur footprints and decide to do some tracking. It looks as if a large herd are moving towards the river, but as the boys approach the marshy area they notice some smaller footprints going a different way. They discover a baby Ankylosaurus in the mud - it's thrashing around and has sunk up to its middle. The baby dino is well and truly stuck. The boys have to find a way of saving the little Ankylosaurus. But when its mother appears will she realize they're trying to help? Or will she come at them with her huge clubbed tail?