British-Irish crime show set in Northern Ireland. Jamie Dornan plays serial killer Paul Spector, who in the first series is portrayed as a serial killer because he grew up in care, no information about his background is given. Series 2 and 3 explore his background a bit more. Metropolitan Police Superintendent Stella Gibson, a senior investigating officer who reviews investigations, is seconded to the Police Service of Northern Ireland (PSNI) to assess the progress of a murder investigation that has remained active for longer than 28 days. When it becomes apparent that a serial killer is on the loose, local detectives must work with Stella to find and capture Paul Spector, who is attacking young professional women in the city of Belfast. As time passes Stella's team works tirelessly to build a case but they are met with complications inside and outside the PSNI.