Newly-moved to the English Cotswolds, Gemma Brown finds a job at the village’s general store and acceptance into a community she soon considers family. With a sharp eye and lively mind, molded by her insatiable love for detective novels, Gemma quickly catches the eye of the local police constable, Harry Charles, and helps him solve cases over pints or sherries at the local pub.

But when Gemma, determined to learn all the “skills” she missed out during a childhood ravaged by WWII, asks the village’s star baker, Ursula Beurton, to give her baking lessons, she starts to notice things that belie the woman’s image as a typical housewife. Is Ursula hiding something or is Gemma’s imagination running away with her?

Yet Gemma knows she does not imagine the two-way radio, uncommon in 1950 and very rare outside military offices, nor she does imagine all the strange places Ursula goes, or the fact that Ursula drops encrypted notes in a tree trunk and pulls envelopes from the same hole. And what about those men she’s seen walking with out the in countryside? Pulling along her new best friend, Peggy, as her faithful sidekick, Gemma begins an investigation of her own to answer a single question: Is Ursula Beurton a spy?

Following her instincts, and a few skills learned through fiction, Gemma and Peggy soon get on the wrong side of the local constabulary, putting Gemma’s budding romance with P.C. Charles at risk, and become embroiled in an international intrigue involving the village’s mysterious benefactor, Lady Beatrice, British Secret Intelligence Services, and the Soviet KGB.

In an unexpected twist, however, Ursula Kuczynski Beurton, KGB codename AGENT SONYA, turns the tables on Gemma and slips through MI5’s fingers, escaping to East Germany on February 27, 1950. But before leaving, she asks Gemma for a favor which may endanger all their lives.