An orchestral conductor has been found dead and Detective Inspector Jack Robinson needs the delightfully incisive and sophisticated Miss Fisher's assistance. Hugh Tregennis has been murdered in a most flamboyant mode by a killer with a point to prove. But how many killers is Phryne really stalking?

At the same time, the dark curls and disdainful air of mathematician and code-breaker Rupert Sheffield are taking Melbourne by storm. They've certainly taken the heart of Phryne's old friend from the trenches of WWI, John Wilson. Phryne recognises Sheffield as a man who attracts danger and is determined to protect John from harm. While Mendelssohn's 'Elijah,' memories of the Great War, and the science of deduction ring in her head, Phryne's past must also play its part as MI6 become involved in the tangled web of murders.