England, 1923: The Honourable Daisy Dalrymple attends a performance of Verdi's Requiem with Detective Chief Inspector Alec Fletcher of Scotland Yard. The tickets were a gift from Muriel Westlea, Daisy's neighbor and the sister of Bettina Westlea, who will be singing the mezzo role. What should be a pleasant afternoon is disrupted when, during the performance, Bettina falls dead on stage--poisoned with cyanide. While it's quickly determined that Bettina's on-stage prop glass of liqueur was laced with the deadly poison, discovering the person responsible will not be an easy task....