When the Police Service of Northern Ireland are unable to close a case after 28 days, Detective Superintendent Stella Gibson of the Metropolitan Police Service is called in to review the case. Under her new leadership, the local detectives must track down and stop a serial killer who is terrorising the city of Belfast.

• Gillian Anderson
• Jamie Dornan
• Niamh McGrady
• John Lynch
• Colin Morgan
• Stuart Graham
• Valene Kane
• Bronagh Waugh