A Perfect Day for Dying — Joyce Christmas

When a posh party in the Caribbean arranged by Lady Margaret's good friend and ne'er-do-well Paul Castrocani, for wealthy Lord Fairfane, provides the setting for two murders, Lady Margaret flies to the scene. An expert in upper-crust mruder, she poses as a party-goer to ferret out the killer. Her snooping uncovers messy little secrets from the Farfaine past, as blackmail, black magic, and deadly rumors expose the dark side of paradise....