Dublin Murders S01E04 - Episode 4

Frank comes up with a plan for Cassie to go undercover as her double to discover who killed her, but she refuses to be involved. However, a savage rejection from Rob that leaves her feeling betrayed leads her to have a change of heart. As the investigation into Katy drags to a halt, Rob becomes fixated on tracking down two of Jonathan's old friends, convinced they are the key to solving both mysteries.