A thrilling historical novel, the fifth in James Green's series charting the development of the Central Intelligence Agency. 1944: the Second World War is going the way of the Allies. Major Bill Evans is an intelligence officer in London, working on the crucial Operation Overlord – the Allied invasion of Western Europe. When a monitored German agent goes missing, suspicion falls on the agent’s landlady – and on Helen Duncan, a well-known medium the landlady has been consulting. Duncan seems to know more than a Scottish housewife should about certain aspects of the war. Is it her supposed access to the spirit world, or is she something more sinister – a Nazi sleeper agent? Evans and his assistant, Penny Coyle, are caught in a quandary when Lieutenant Joe Sparrow of US Intelligence gets involved. Just who is Lieutenant Sparrow – and why is he so keen to get Helen Duncan locked up? It seems the trail leads all the way to the top – to Churchill himself…