Christmas Day1943, Arisaig, Scotland. The body of beautiful, well-connected Polish SOE agent Krystina Kowolska is found in the gardens of the country house where she’s been preparing for a vital mission to France. The question is, was she already dead when she was hanged? Two days later, resistance double agent, Investigator Jan Kalisz of the Warsaw Kripo is flown to Britain where Winston Churchill tasks him with finding Krystina’s killer before the cracks in Britain’s alliance with Poland become fractures. Yet Arisaig is a place of secrets where every man is a trained killer and Kalisz discovers that Krystina had her demons – and her enemies. Was she the heroine her record suggests or the traitor the whispers hint at? Despite being resented as an interloper and blocked at every turn, Kalisz eventually discovers a secret definitely worth killing for. It seems the answer lies in the past, but whose past?