All spies have secrets, but Henry Hunter has more than most. After he is stopped by British Intelligence at Croydon airport on the eve of the Second World War, he discovers one more devastating than any before. From Switzerland he embarks on a series of increasingly perilous missions into Nazi Germany, all while having to cope with various identities and competing spymasters. In March, 1941, in Berlin, haunted by a dark episode from his past, he makes a fateful decision, resulting in a dramatic journey to the Swiss frontier and a shocking encounter.