When River and Ira uncover what Stevie was investigating before her murder, it leads to the discovery of a new suspect. But breakthroughs in the case have devastating implications for another member of the team.

Cast: Stellan Skarsgård, Nicola Walker, Lesley Manville, Eddie Marsan, Adeel Akhtar, Michael Maloney, Georgina Rich, Owen Teale, Lydia Leonard, Anamaria Marinca, Adjoa Andoh, Jim Norton, Sorcha Cusack, Steve Nicolson, Turlough Convery