Lady Rosamund Phipps, daughter of an earl, has a secret. Well, more than one. Such as the fact that she’s so uninterested in sex that she married a man who promised to leave her alone and stick to his mistress. And a secret only her family knows—the mortifying compulsion to check things over and over. Society condemns people like her to asylums. But when she discovers the dead body of a footman on the stairs, everything she’s tried to hide for years may be spilled out in broad daylight. First the anonymous caricaturist, Corvus, implicates Lady Rosamund in a series of scandalous prints. Worse, though, are the poison pen letters that indicate someone knows the shameful secret of her compulsions. She cannot do detective work on her own without seeming odder than she already is, but she has no choice if she is to unmask both Corvus and the poison pen. Will Corvus prove to be an ally or an enemy? With the anonymous poison pen still out there, her sanity—and her life—are at stake.

Widowed Lady Rosamund spends the first months of her mourning in the Lake District, where it’s safe and peaceful, and murders are exceedingly rare. Luckily, she is rescued from this tedium by a house party comprised of playwrights, poets, and actors—an immoral set of persons with whom no respectable lady should associate. Even so, she hardly expected to wake in the wee hours to find one of the guests lying dead. As if that wasn’t troublesome enough, Gilroy McBrae is at the same party, masquerading as a footman to investigate a series of thefts. Was the sudden death an accident—or murder? Almost everyone had reason to loathe their unpleasant fellow guest. Rosie must set aside her confused emotions about McBrae and work with him to find the culprit before an innocent person is accused of the crime.

Lady Rosamund’s plan for a quiet return to London society goes awry when she rescues a woman fleeing along the road—the mistress of her brother, Lord Derwent. Rosamund takes her in, meaning to sort matters out with Derwent—but he has left town in a hurry, and soon the Bow Street Runners are after him for murder. If that wasn’t trouble enough, several suitors are vying for Lady Rosamund’s hand. Luckily, Gilroy McBrae is in London to help Rosamund save her brother. Will their strained relationship, along with his rivals for her heart, impede the race to unmask the real murderer before Derwent is caught and hanged?