Twenty-six-year-old Maggie Barnes is someone you would never look at twice. Living alone in a month-to-month sublet in London, with no family but an estranged sister, no boyfriend or partner, and not much in the way of friends, Maggie is just the kind of person who could vanish from the face of the earth without anyone taking notice.

Or just the kind of person MI5 needs to thwart an international plot that puts all of Britain at risk.

One woman, one chance to be a hero: the trick is to stay alive.

Mick Herron sets aside his superlative Jackson Lamb series for an unnerving, standalone take on contemporary espionage. Split between Maggie, her sister Meredith and her MI5 handler Harvey, Herron’s portrait simmers with authenticity and danger as the truth of Maggie’s mission begins to bubble to the surface.