What happens when one's commitment to their duty conflicts with the loyalty to their country? That is the dilemma facing Detective Superintendent Douglas Archer in Len Deighton's alternate history thriller. A leading member of Scotland Yard's Murder Squad, he finds himself working for the German occupation in the aftermath of their conquest of Great Britain. This tension becomes unavoidable when Archer is called upon to investigate the murder of a man found in an apartment in Shepherd Market. Though initially unremarkable, the case quickly draws attention from the highest circles of the German government, as Archer finds himself pulled into a dangerous world of political intrigue that forces him to resolve his priorities and take a side - no matter what the cost.
Deighton's book is an dramatic story of intrigue in a world that might have been. He does not explain up front how Britain was defeated or what the point of divergence was, leaving details to trickle out naturally as they would in a normal conversation, without any of the clunky exposition too many writers adopt when explaining the worlds they have constructed. Instead his focus is on the plot and characters, as he constructs a grim yet plausible world in which a depressed population is still coming to terms with their defeat. The mystery itself unfolds gradually, and while some readers may figure out the particulars fairly quickly Deighton still puts together an ending that is difficult to forecast before getting there. Taken together, it makes for one of the best alternate history novels ever written, as well as a suspenseful tale that readers who are not familiar with the genre will enjoy nonetheless.