The Honourable Daisy Dalrymple attends a performance of Verdi's Requiem with Detective Chief Inspector Alec Fletcher of Scotland Yard. What should be a pleasant afternoon is disrupted when, during the performance, Bettina Westlea, the mezzo-soprano, falls dead onstage. But it was no accident - she was poisoned with cyanide. Bettina was neither well liked nor well behaved, and many of her colleagues, associates, and even her family had good reason to want her dead. Daisy, determined to help DCI Fletcher whether he wants help or not, decides to do some investigating on her own. But with so many suspects and so few clues, the murderer may well go free.