Josie is fascinated with the secrets of the prehistoric world. She and her grandfather, an amateur paleontologist, explore the beaches and cliffs near Stone Trees Cottage in Nova Scotia. Tiny bones have been discovered, but what are they from? As Josie searches for the answer, she is forced to cope with an accident and competition from an unpleasant neighbor. Time is of the essence, for she must find the answer before someone else does and before the tides and waves that exposed the secret wash it away forever.