Line of Duty, the cops-versus-cops series filmed in Northern Ireland, returns for a third season tonight at 9 pm on BBC 2.
It's a year and a half since the end of series two. Superintendent Ted Hastings (Adrian Dunbar) has separated from his wife, his colleague DC Kate Fleming (Vicky McClure) is no longer living in a car but in an apartment, and Steve Arnott (Martin Compston) is in a steady relationship with another police officer.
The six-part serial opens with the fatal shooting of a criminal suspect by an armed response unit led by Sergeant Danny Waldron (Daniel Mays).
He and his unit claim they acted in self-defence. But the AC-12 team, led by Superintendent Hastings, gather evidence that suggests it was a deliberate killing. DC Kate Fleming goes undercover into Danny’s unit to find out more.