When evidence presented in court by Thomas Pitt leads to the execution of a distinguished soldier and archaeologist, the retaliation from the hanged man's influential friends is swift. The murderer was a member of the Inner Circle, a group of men whose power extends further than Pitt realised was possible, and, within days, he loses command of the Bow Street police station. To protect him from the Inner Circle's hatred, he is forced to leave his family to work undercover in the dangerously volatile East End.