Luke remains in the Medway as the government is convinced that a foreign invasion with local gentry assistance is imminent. The disappearance of a senior officer and strange activities on the river attract Luke’s attention. Luke is appalled at the confused military situation and the divided loyalties within the household of the powerful landowner Lady Prudence, whom Cromwell asks to assist in ways that are not explained. Does the despicable Harry Proctor—smuggler, womanizer, gambler and useless soldier—become a serial killer? And why is he protected by senior members of the household. Women—the trawler fleet owner who is kidnapped, the alluring wife of a local magistrate, the spoilt child who facilitates a murder, and the enduring but mystifying influence of the deceased Lady Mary—complicate the situation.
Luke is worried by foreigners realigning strategic guns, the misdirection of trawlers to collect protestant refugees whom Luke suspects to be a Royalist vanguard, and visits by local identities to the continent.
Luke survives shooting, drowning, a horse accident, and mob beating to solve murders, uncover the local gentry traitors, and identify the person who is both the brains behind the Royalist conspiracy, and the agent to complete Lady Mary’s revenge.