First published in 1956, and this edition printed by Pan in 1966.
Although printed in England, I think this copy was destined for Australia as on the back cover is:
60c AUSTRALIA 6/-
A fete at a country house in Devon, and the well-known thriller writer Ariadne Oliver has organised a Treasure Hunt with a difference - a Murder Hunt.
But Mrs Oliver feels, unaccountably, that all is not well, and she calls in that celebrated detective M. Mercule Poirot, ostensibly to give away the prizes. And her fears are justified when the 'body' is found - this corpse is very dead...