Castle is approaching retirement from MI6 where he has been an officer in the Africa section for a number of years following active service in the continent. He is married to a black South African lady who he helped escape from the apartheid regime. He is enjoying his quiet and uneventful life, when him and his assistant, Davis, are interviewed following the discovery of a leak in the service that has been traced back to his department. The investigation concludes that Davis is the source of the leak and action is taken, but the cloud of suspicion still hangs over Castle and he realises that he may have to make a greater sacrifice to save all that he cherishes.
To write this tense thriller Green drew on all his experience and knowledge from his time at MI6 during the Second World War. It is a bleak story, that is very cleverly written too, as he has managed to get across the mundaneness of the bureaucrat’s job in the service, whilst examining the larger question of loyalty to family or to country. I really liked the subtlety of the writing too. It doesn’t have the glamour and excitement of some spy fiction, but it does have the drama.