Two years ago, a hostile Prime Minister launched the Monochrome inquiry, investigating "historical over-reaching" by the British Secret Service “to investigate historical over-reaching.” Monochrome’s mission was to ferret out any hint of misconduct by any MI5 officer—and allowed Griselda Fleet and Malcolm Kyle, the two civil servants seconded to the project, unfettered access to any and all confidential information in the Service archives in order to do so. But MI5’s formidable First Desk did not become Britain’s top spy by accident, and she has successfully thwarted the inquiry at every turn.

When a young man breaks into South Oxford Nursery School with a gun and takes a group of hostages, teacher Louise Kennedy is fearful. But Jaime Segura isn’t there on a homicidal mission. Bad Sam Chapman - head of the intelligence service’s internal security force, the Dogs - tries to find out what Jaime is after. But the only person Jaime will talk to is Ben Whistler, an MI6 colleague of Jaime’s lover, Miro - who has gone missing with a quarter of a billion pounds....

When a house explodes in a quiet Oxford suburb and a young girl disappears in the aftermath, Sarah Tucker becomes obsessed with finding her. Accustomed to dull chores in a childless household and hosting her husband’s wearisome business clients for dinner, Sarah suddenly finds herself questioning everything she thought she knew, as her investigation reveals that people long believed dead are still among the living, while the living are fast joining the dead.

When a body is hauled from the River Tyne, Sarah Tucker heads to Newcastle for a closer look. She identifies the dead woman as Private Detective Zoë Boehm, but putting a name to the corpse only raises further questions. Did Zoë kill herself, or did one of her old cases come back to haunt her? Coincidence is an excuse that soon appears pretty unconvincing. Sarah can’t leave until she’s found the answers to her questions, however dangerous they might turn out to be.

When Caroline Daniels takes a deadly fall in front of a train and her lover fails to turn up at the funeral, Zoë Boehm wants nothing to do with the case. But Caroline's boss is persistent, and as Zoë attempts to unlock the secrets of a woman she's never met while in search of a man who could be anywhere, she starts to wonder if he's found her first. And if he has, will that make her the next victim?