Trama

Drama series following the investigations of AC-12, a controversial police anti-corruption unit tasked with bringing corrupt police officers to justice.

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.—World Productions

DS Steve Arnott is transferred to Central Police's Anti-Corruption Unit, AC-12 after his Counter Terrorism team shoot dead an innocent man in a botched raid. There he works with DC/DS/DI Kate Fleming and Superintendent Ted Hastings who across the series uncover a clandestine network of corrupt police officers in collusion with a deadly Organised Crime Group.—ahmetkozan

Police Sergeant Steve Arnott is forced out of the Anti-Terrorism unit when an operation goes terribly wrong and he refuses to cover up the truth. He finds himself in AC-12, an anti-corruption unit tasked with finding, investigating and arresting corrupt police officers. The unit is run by Superintendent Ted Hastings, an old school, by-the-book policeman with a passion for exposing police corruption. His zeal, and the fact that AC-12 even exists, often makes AC-12 pariahs within their own police force.—grantss

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.

Series 1 focuses on Detective Constable Inspector Anthony "Tony" Gates (Lennie James) an officer of the year and head of the serious crime unit TO-20, who is renowned for returning the best crime figures of any unit in Central Police. It is this reputation, however, that leads AC-12 to his team. Suspected of "laddering" - attributing numerous different charges to the same defendant to increase an officer's number of successful cases, Gates faces an internal affairs investigation that adds further complications to his troubled home-life.

Series 2 focuses on Detective Inspector Lindsay Denton (Keeley Hawes), a silver commander who organizes a convoy to transport a protected witness which is ambushed, resulting in the deaths of all the other police officers. As the only police survivor, Denton is arrested, charged with conspiracy to commit murder. She attempts to convince AC-12 of her innocence and regain her reputation, but eventually receives a life sentence.

Series 3 focuses on Sergeant Daniel "Danny" Waldron (Daniel Mays) an Authorised Firearms Officer (A.F.O.). His armed response unit is investigated by AC-12, as a matter of routine following the shooting of a suspect. A deeper investigation is initiated when Arnott and Fleming discover the shooting may have been unlawful.

Series 4 focuses on Detective Chief Inspector Roseanne "Roz" Huntley (Thandiwe Newton) the senior investigating officer of "Operation Trapdoor", whose mission is to identify and capture a suspected serial killer. After the arrest of a man with learning difficulties, Roz becomes the centre of an AC-12 investigation for mishandling evidence that could exonerate the innocent man.

Series 5 focuses on undercover officer Detective Sergeant John Corbett (Stephen Graham), an undercover police officer of "Operation Pear Tree" who has been uncontactable for several months. He first appears as John Clayton, the gang-leader of an organized crime group that hijacked a police convoy transporting seized drugs.

Series 6 focuses on Detective Cheif Inspector Joanne 'Jo' Davidson (Kelly Macdonald), the Senior Investigating Officer of "Operation Lighthouse", whose investigation into the unsolved murder of a journalist, Gail Vella, whose unconventional conduct raises suspicions at AC-12.

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.