Line Of Duty

A brutal ambush on a police convoy leaves three officers dead and a protected witness fighting for his life. AC-12 turns its spotlight on Lindsay Denton, the officer who led the convoy but escaped unscathed.

Following the tragedy at the hospital, AC12's Kate Fleming is planted undercover in Lindsay Denton's 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. DCC Dryden shrugs off allegations about his relationship with Lindsay and possible links to the ambush.

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

When a criminal is shot dead by a police armed-response unit led by Sergeant Danny Waldron, AC-12 gather evidence suggesting it was a deliberate killing rather than self-defense.

Danny's armed-response unit come under increasing scrutiny as AC-12 feed Kate information to help her crack their story. Steve makes a shocking discovery, then his own past catches up with him.

DS Steve Arnott believes there is a dark secret in Danny Waldron's past. Then the spotlight falls on his questionable conduct in a previous inquiry - the Lindsay Denton case.

Fresh testimony launches AC-12 back on the trail of the Caddy, a corrupt officer with links to organized crime.

AC-12's loyalties are divided when DS Arnott comes under scrutiny from his colleagues.

When DCI Roz Huntley captures a serial killer, Forensic Coordinator Tim Ifield alerts AC-12 to a possible miscarriage of justice.

A dismembered body is discovered, and worries grow when Roz fails to report for duty. After further questioning of Michael Farmer unearths crucial new information, AC-12 challenge the case against him.

As shocking new evidence is unearthed, AC-12 step up their investigation in to the case against Michael Farmer.

The discovery of new forensic anomalies appears to provide AC-12 with a major breakthrough. Meanwhile, Nick Huntley comes under scrutiny.

AC-12's future hangs in the balance after Hilton bars them from investigating Roz Huntley. But Roz's problems are building closer to home.

When three police officers are shot dead during the hijack of a seized drugs transport, AC-12 move in to investigate possible police collusion.

A fresh police leak enables another audacious raid, while Arnott's attempts to gather information put him in a dangerous situation.

Corbett's most daring plan yet requires McQueen to exploit links with corrupt police officers. Meanwhile, the AC-12 team make a shocking discovery.

Tensions rise in the OCG following the events at Eastfield. With troubling questions hanging over the identity of the mysterious H, suspicions mount among the AC-12 team.

As the hunt for H intensifies, Steve and Kate wonder if Hastings is guarding a dark secret.