When retired former spy Felicity Jardine's mission to drown herself is interrupted by a baby drifting down river, her training kicks in at once. She manages to save the baby, and conceals them both from the shady-looking man who is searching for it. Then an elderly neighbour to whom she bears a resemblance is found dead, and Felicity knows she's been rumbled. She has to dust off the highly trained and resourceful secret service officer she used to be, ensure the safety of the baby, and re-enter the fray. She can count on the help of two former MI6 colleagues to identify the murderer and find out exactly what's going on. But Felicity will soon realise that her work in 1970s Germany and her present are entangled – and she will have to face some hard truths before she can confront the demons of her past.