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?