After a Yorkshire spa trip during which she survived a near brush with death and foiled a murderer, aspiring writer Aggie Morton and her friend Hector are thrilled to stay at a camp by the sea and watch palaeontologists at work. The husband and wife team of the Blenningham-Crewes are trying to recover the fossilized bones of an ichthyosaur. The news has the attention of an American millionaire, a British museum and a travelling circus owner, who each want the bones for their own collections. Soon, Aggie and Hector make a discovery of their own: a body on the beach.
