Line of Duty

A brutal ambush on a police convoy leaves three officers dead and a protected witness fighting for his life. AC-12 - Ted Hastings, Steve Arnott and new recruit Georgia Trotman - turn their spotlight on Lindsay Denton.

Following the tragedy at the hospital, AC12's Kate Fleming (Vicky McClure) is planted undercover in Lindsay Denton's (Keeley Hawes) Missing Persons Unit. But Lindsay in turn gathers compromising evidence against the anti-corruption team.

Lindsay is denied bail and finds herself targeted in prison. Growing increasingly desperate, she tells Kate about a relationship with an executive police officer and her theory of why she is being framed.

Following the violent attack she suffered in prison, Lindsay is granted special dispensation to visit her dying mother. Meanwhile Deputy Chief Constable Dryden shrugs off allegations about his relationship with Lindsay.

Lindsay fights for her life as troubling details emerge of a vicious conspiracy involving corrupt police officers. With growing evidence of links between DCC Dryden and the ambush, Hastings is under pressure to arrest his senior officer.

AC12's investigation finally exposes a vicious criminal gang run from within the police. But while Steve now appears convinced of Lindsay's innocence, Kate remains determined to prove she had a role in the ambush.