Sam Riley and Kate Bosworth star in this five-part BBC drama set in an alternate past where Germany won the Second World War and the Nazis occupy Britain. Based on Len Deighton's novel, the show is set in 1941 and follows widowed Detective Superintendent Douglas Archer (Riley), of London's Metropolitan Police, as he begins investigating the suspected murder of an antique shop owner, who seems to have ties to the British resistance. It's not long before a German SS officer replaces Douglas on the case but, despite his orders, he continues his investigations which lead him to American journalist Barbara Barga (Bosworth), who his boss Fritz Kellermann (Rainer Bock) suspects is procuring American aid to defeat the Germans. As he delves deeper into the mystery and uncovers bigger, more sinister plots, Douglas finds himself questioning his loyalty to his commanders and his attitude towards the resistance.