All six episodes of the British crime drama starring Ukweli Roach as DI Jack Caffery, whose ten-year-old brother Ewan disappeared over 20 years ago. Believing his parents' neighbour Ivan Penderecki (Anthony Webster) is responsible for Ewan's abduction and possible murder, when Caffery returns to London from Wales, he begins survelling Penderecki. At the same time, he is quietly reinvestigating a murder case that he worked on in Wales, as he is concerned that they may have arrested the wrong man.

Meanwhile, on the anniversary of that crime, Matilda Anchor-Ferrers (Juliet Stevenson), her husband, Oliver (Owen Teale), and their daughter, Lucia (Annes Elwy), travel to their house in Wales, where two men are waiting for them... The episodes are: 'Watching', 'Torture', 'Scary Man', 'Night Terror', 'Death Roll' and 'Knock, Knock'.