As a favor to her dear friend, Ivy, Lady Emily Ashton attends a weekend affair hosted by Lord Basil Fortescue, an unpleasant man with powerful political ties. Ivy's husband, Robert Brandon, was Lord Fortescue's protégé until a terrible argument has Lord Fortescue dismissing Robert. Shortly thereafter, Lord Fortescue is found murdered with the evidence pointing to Robert. With the police assured of his guilt, Ivy begs Emily, who has had success in the past with solving mysteries, to find the killer.

The clues lead Emily to an anarchist in Vienna. Colin Hargreaves, Emily's fiancé and a covert operative, is involved in a case and cannot accompany her. In Vienna, Emily reluctantly asks Colin's former lover, Countess von Lange for help. The countess wants Colin back and instigates trouble and doubt into Emily's relationship. Emily wants to trust Colin, but she believes past love always remains in part of your heart.

Emily copes with the political intrigues that are abundant in Vienna and painstakingly works to find evidence to save Robert from the gallows. Colin appears unexpectedly and helps Emily in her investigation. For the first time, Emily sees the reality of Colin's work. The equality Emily strives for in their relationship is no longer abstract and comes at an emotional cost. As their cases intertwine, Emily and Colin have death threats made against them, making time of the essence in discovering the anarchist's plot and exposing the killer.

Ms. Alexander's latest Lady Emily mystery is rich in historical detail as she captures the complex social and political climate in Vienna. Her insightful characters understand their human flaws and the compromises they must make. Ms. Alexander weaves fictional characters with the real historical ones in this cleverly plotted and suspenseful mystery.