Charles Lenox is at the pinnacle of his political career and is a delighted new father. His days of regularly investigating the crimes of Victorian London now some years behind him, he plans a trip to his uncle's estate, Somerset, in the expectation of a few calm weeks to write an important speech. When he arrives in the quiet village of Plumley, however, what greets him is a series of strange vandalisms upon the local shops: broken windows, minor thefts, threatening scrawls.

Only when a far more serious crime is committed does he begin to understand the great stakes of those events, and the complex and sinister mind that is wreaking fear and suspicion in Plumley. Now, with his protege, John Dallington, at his side, the race is on for Lenox to find the culprit before he strikes again. And this time his victim may be someone that Lenox loves.