On a sunny afternoon in late June, Cambridge professor Joseph Reavley is summoned from a student cricket match to learn that his parents have died in an automobile crash. Joseph’s brother, Matthew, as officer in the Intelligence Service, reveals that their father had been en route to London to turn over to him a mysterious secret document—allegedly with the power to disgrace England forever and destroy the civilized world. A paper so damning that Joseph and Matthew dared mention it only to their restless younger sister. Now it has vanished.

His name, they tell him, is William Monk, and he is a London police detective. But the accident that felled him has left him with only half a life; his memory and his entire past have vanished. As he tries to hide the truth, Monk returns to work and is assigned to investigate the brutal murder of a Crimean War hero and man about town. Which makes Monk’s efforts doubly difficult, since he’s forgotten his professional skills along with everything else.

When a maid in the upper class Ellison household is strangled, Inspector Pitt is called in to investigate. He finds a world ruled by strict manners and social customs, where the inhabitants of the Ellison's neighborhood appear to be more outraged by the thought of scandal than they are by murder. Inspector Pitt finds a most unlikely ally in Charlotte, the Ellison's spirited daughter. But as the murders continue, Charlotte and Pitt find themselves drawn together by more than the investigation.

As commander of the River Police, Monk is accustomed to violent death, but the mutilated female body found on Limehouse Pier one chilly December morning moves him with horror and pity. The victim’s name is Zenia Gadney. Her waterfront neighbors can tell him little—only that the same unknown gentleman had visited her once a month for many years. She must be a prostitute, but—described as quiet and kempt—she doesn’t appear to be a fallen woman. What sinister secrets could have made poor Zenia worth killing? And why does the government keep interfering in Monk’s investigation?

The pope is dead. Behind the locked doors of the Sistine Chapel, 118 cardinals from all over the globe will cast their votes in the world's most secretive election. They are holy men. But they have ambition. And they have rivals. Over the next 72 hours, one of them will become the most powerful spiritual figure on earth.