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?