Ep 4. Episode 4

Detective Inspector Lindsay Denton has been in a car accident, which appears to have been an attempt to kill her. She is hospitalized and her colleagues try to figure out who might have wanted to hurt her. Superintendent Hastings believes it is connected to the case they are currently working on – the investigation of an armed robbery in which a gang of four men stole millions of pounds worth of drugs and cash from a security van. It appears that Denton may have been in possession of some key evidence, so they fear that whoever is behind the robbery might also be behind the attempt on Denton's life.

Detective Sergeant Steve Arnott is still undercover as a member of the robbery gang, and is struggling to maintain his cover as tensions rise among the group. He is particularly worried about one of the members – Carl Banks – who seems to be planning something dangerous. Arnott tries to warn his colleagues but they are skeptical, as Banks has never been known to be violent before.

Meanwhile, Detective Constable Kate Fleming is trying to get more information about Denton's past, as she believes it may hold some clues to the case. She discovers that Denton was accused of falsifying evidence and perjury in a previous case, and was subsequently demoted. However, she was later reinstated due to lack of evidence. This discovery leads Kate to suspect that Denton may be involved in the current case in a more sinister way than they had initially thought.

As the investigation progresses, it becomes clear that Denton's accident was no accident, and that she is in fact the prime suspect in the robbery case. However, she is nowhere to be found, and is suspected to have gone on the run. Arnott, who is still undercover, is tasked with tracking her down, and his loyalty is tested as he grapples with conflicting emotions about Denton and his duty to the police force.

In the climactic finale, tensions reach boiling point as Arnott finally confronts Banks and uncovers the shocking truth behind the robbery – a discovery that puts his life in danger. Meanwhile, Fleming races against time to find Denton and bring her to justice before it's too late. In the end, the team must come to terms with the shocking revelations they have uncovered, and the consequences of their actions.