(Sky Atlantic) For season four, the most successful German TV drama ever made increasingly plunged the viewer into darkness. As the neo-noir crime show’s tale of Weimar-era Berlin grew ever closer to the advent of Nazi rule, lead detective Gereon Rath infiltrated the organisation in plots that became ever more menacing, while the wreckage of the 1929 financial crash destroyed lives all around him. More than ever, there was a desperate, poignant edge to the cabaret debauchery, as it became a refuge from the terrifying world outside, and this series served up 10 episodes of utterly gripping television.