Secrets in Stones

A polyglot group of archaeologists, tourists, and journalists gather in the atmospheric Vallée des Prêtres , high up in the Franco-Italian Alps. They are there to witness the authentication by renowned archaeologist, Sir Hilary Compton, of Bronze Age rock drawings recently discovered by up and coming young archaeologist, Oliver Hardcastle.
When Sir Hilary deems the new drawings fakes tensions among the academics run high. Then Oliver hardcastle's body is found floating in a treacherous pool named the Lake of Shadows.
Private investigator, Ulysses F Donaghue, who numbers amongst the tourists is called upon to investigate Hardcastle's death.
With its unexpected twist in the tail, Secrets in Stones confirms the Donaghue mysteries as perfect descendants of the classic Christie whodunit.