Given Charlotte Philby’s background — she is the granddaughter of the KGB agent Kim — one might expect this to be a spy novel, and there are traces of that. Yet this tale of a life spinning out of control is closer to Patricia Highsmith territory. Gabriela is a counterterror specialist who stumbles into a conspiracy, while journalist Isobel investigates after seeing a woman attacked on Hampstead Heath. What links the two women? Subterfuge, paranoia and chills galore.