A maid disappears from the Blackheath home of Dudley Kynaston, a naval weapons expert whose work is important to British defence. When a mutilated body is found nearby, Thomas Pitt must determine whether the death is a domestic crime, an attempt at blackmail or part of a larger effort to obtain military secrets.
Special Branch pressure requires Pitt to protect Kynaston’s research without suppressing evidence that may implicate the household. Charlotte’s inquiries among the servants and family expose deception on both sides of the class divide and a plot designed to make Pitt responsible for its failure.