Lured by the promise of a rare butterfly, Veronica Speedwell is persuaded by Lord Templeton-Vane, the brother of her colleague Stoker, to pose as his fiancée at a party on a Cornish isle owned by his oldest friend, Malcolm Romilly. But in this fourth adventure (following A Treacherous Curse), one question hangs over the party: What happened to Rosamund? Three years ago, Malcolm Romilly's bride vanished on their wedding day, and no trace of her has ever been found. From the poison garden kept by Malcolm's sister to the high towers of the family castle, danger lurks around every corner, and Veronica and Stoker must match wits with a murderer who will not hesitate to kill again.