Line of Duty
A sergeant who refuses to be involved in a police cover-up joins an anti-corruption team.
Episode 1
S5 E1
When three police officers are shot dead during the hijacking of a seized-drugs transport, AC-12 moves in to investigate possible police collusion.
The Head of Medusa
S5 E2
Kate and Steve attempt to track down a lead; a fresh police leak enables another audacious raid; Steve's attempts to gather information put him in a dangerous situation.
Code Zero
S5 E3
Corbett's most daring plan yet requires McQueen to exploit links with corrupt police officers; AC-12 makes a shocking discovery.
Episode 5
S5 E5
As the hunt for "H" intensifies, Steve and Kate wonder if Hastings is guarding a dark secret.
Episode 6
S5 E6
As Hastings's secrets are laid bare, Kate and Steve are torn between loyalty and their duty to uncover the truth. Will the identity of "H" be revealed at last?
In the Shadow of Truth
S4 E1
DCI Roz Huntley is under intense pressure from her superiors to apprehend a serial murderer after months of fruitless investigation. When another young woman is abducted, Roz is on the scene to track down and charge a 24-year-old man.
Who Sows the Wind
S4 E2
A dismembered body is discovered, and worries grow when DCI Roz Huntley fails to report for duty. AC-12 crank up their investigation into Operation Trapdoor, concerned that Michael Farmer will go to jail for crimes he didn't commit.
Moral Superiority
S4 E4
Nick is brought in for questioning by AC-12, but while Nick denies any involvement in Steve's attack, his suspicions about Roz mount. AC-12 discover new anomalies in the forensic evidence and issue DCI Roz Huntley with a second Reg 15 notice.
Lying Nest
S4 E5
DCI Roz Huntley struggles to allay her husband's suspicions. AC-12 find a new angle to pursue their case against her.
Royal Hunting Ground
S4 E6
While Nick Huntley faces lengthy questioning over his role in Tim Ifield's murder, AC-12 remain convinced of Roz's involvement.
Explanations
S3 E1
Sergeant Danny Waldron and his armed response team shoot dead a hardened criminal, but soon cracks appear in their story.
Line of Duty
S3 E2
DC Kate Fleming uses her undercover role to increase the pressure on Danny Waldron's armed response unit; an old AC-12 investigation comes under legal scrutiny.
Move On
S3 E4
Lindsay Denton sets out to clear her name, while Arnott and Hastings interrogate Bains on suspicion of murder.
The List
S3 E5
Steve Arnott's colleagues scrutinize him.
Getting to the Truth
S3 E6
DS Steve Arnott is arrested on suspicion of murder.
The Ambush
S2 E1
A brutal ambush on a police convoy leaves three officers dead and a protected witness fighting for his life; AC-12 turns their spotlight on the officer who led the convoy.
Carly
S2 E2
Kate Fleming is planted undercover in Lindsay Denton's Missing Persons Unit.
Blood Money
S2 E4
Lindsay is granted special dispensation to visit her dying mother.
Taste of Freedom
S2 E5
Lindsay fights for her life as troubling details emerge of a vicious conspiracy.
The Caddy
S2 E6
AC12's investigation finally exposes a vicious criminal gang run from within the police.
A Disastrous Affair
S1 E1
When Steve Arnott is transferred to AC-12, his first assignment is to investigate the city's top detective, DCI Tony Gates.
Line of Duty
S1 E2
Having been duped into covering up Jackie's crime, Gates is desperate to sever ties with her; as Arnott and Fleming close in on his secret, Gates is plunged into a more dangerous situation.
Terror
S1 E4
Desperate for proof of Gates's corruption, Fleming pushes her relationship with him to the limit.
The Probation
S1 E5
With Gates on the run, the anti-corruption team comes under pressure to close the case; Arnott is forced to make some tough decisions about his loyalties; Fleming and Hastings go all out to catch Gates.