London, 1785. When the body of a West Indies planter is found pegged out in the grounds of St Paul's, suspicion falls on one of the victim's former slaves, who was found with his watch on the London streets. As Harriet and Crowther begin investigate, however, they find the answer is not that simple. Together, they negotiate the interests of the British government, the secrets of the plantation owners, and a network of alliances stretching across the Atlantic. And they must confront the uncomfortable truth that some people are willing to do great evil when they believe their cause to be just.