Line of Duty on Hulu – Line of Duty Storyline

Line of Duty follows Detective Seargent Steven “Steve” Arnott (Martin Compston), a former authorized firearms officer who led an operation to catch an Islamic terrorist intending to detonate a bomb, but the strike team mistakenly entered the wrong apartment and shot dead an unarmed innocent man.

In the subsequent investigation, Arnott refused to cover up negligence in the planning and execution of the raid and unable to work in his unit anymore, Arnott receives a transfer to AC-12, a unit tasked with uncovering police corruption. Arnott is partnered with Detective Constable Kathrine “Kate” Fleming (Vicky McClure), a highly commended undercover officer with a keen investigative instinct.

They work under the supervision of Superintendent Edward “Ted” Hastings (Adrian Dunbar), who is one of several Senior Investigating Officers responsible for uncovering corruption within the police force.

Throughout the series, AC-12 investigate seemingly disparate cases involving seemingly corrupt police officers, with each series focusing on a different corrupt officer and AC-12 soon realize the pervasive nature of corruption and the police’s deep-rooted links to an organized crime group with ties to drug running, prostitution, child exploitation and people trafficking.

Line of Duty on Hulu – Line of Duty Episode Summary

Season 1, Episode 1
A Disastrous Affair
After a bungled raid which kills an innocent man young DS Steve Arnott faces disgrace.

However he is transferred to the anti-corruption squad, whose head, superintendent Ted Hastings, gives him a “very special case” to investigate – DCI Tony Gates, recently awarded a medal for heroic conduct but with a suspiciously high arrest rate.

Hastings tries to get Gates on minor bribery charges, in vain, and is unaware that the married Gates has covered up a fatal hit-and-run by his lover, businesswoman Jackie Laverty. 

Season 1, Episode 2
The Assault
Having been duped into covering up Jackie’s hit and run, Gates is desperate to sever ties with her.

But as Arnott and Fleming close in on his secret, Gates is plunged into an even more dangerous situation.

Season 1, Episode 3
In the Trap
Gates, knocked unconscious by the attackers, tampers with evidence, hiding a whiskey glass before police arrive to find Jackie has vanished.

He claims he has just got there himself.

Hastings and Arnott quiz him on his relationship with Jackie and he admits she was an old flame but denies knowledge of her money laundering.

Arnott goes over the top in confronting him with evidence to suggest he was at Jackie’s house when she was killed but makes himself look desperate.

Season 1, Episode 4
S1, Ep4
Whilst the money laundering investigation is passed to Fraud Squad, Gates is still hounded by his blackmailers.

Kate wants to connect him to Jackie’s murder and sets out to gain his trust to find further proof though Gates’ loyal colleague Morton rumbles her.

Hastings and Arnott interview Gates’ team and learn from D.S. Cottan that he diverted them from attending the drug dealers’ murders, leading them to believe that Gates knew that the dead pair were working with Jackie though Gates persuades his gullible superior that the couple were in fact terrorists.

Season 1, Episode 5
The Probation
Gates returns to rescue Arnott but leaves before Kate, her cover now blown, arrives to find evidence that a body had been stored at the warehouse.

Arnott recalls that the chief torturer was called Tommy and admits to Kate that Gates saved him.

She believes he is weakening in his attitude to Gates, whom he goes to see in secret, confirming his view that Gates is innocent of all the murders.

Convinced that Gates is in danger but can bring the killers to justice Arnott persuades Hastings to let Gates set up a meeting with Tommy, recorded on a wire.