In the final installment of Martin Cruz Smith’s celebrated Arkady Renko series, the legendary Moscow investigator seeks to solve the murder of a diplomat as Russia’s invasion of Ukraine wears on and the effects of Arkady’s Parkinson’s disease worsen. Helped by his lover, journalist Tatiana Petrovna, Arkady traces the murder to a Russian paramilitary group aided by a government official who also used to be a romantic partner of Arkady. Before long, those responsible for the killing look to similarly dispatch Arkady and Tatiana --- all of it leading to a thrilling and action-packed climax.