Detective Harry Virdee throws himself into the search for a missing teen, caught up in a county lines drug gang. Following an emotional appeal from the boy's mother, Harry is tempted to cross a dangerous line.

When tensions flare between rival gangs due to a murder that rocks Bradford's underworld, Harry's search for the killer leads him to the victim's ex-boyfriend, discovering details of her secret life; Saima makes a risky attempt to mend family ties.

As Bradford reels from the nightclub attack, the killer ups the ante with a high-profile kidnapping. The UK Crime Agency descends on Bradford, putting Harry and Conway's roles into question.

The killer's game turns personal when a tense phone call at police headquarters forces Harry to relive a trauma from his past; a chance discovery prompts Saima to question what she knows about Harry and her brother.

With Harry hospitalised after a life-threatening attack, the killer contacts the police with an offer; Riaz becomes a target as Vasil seeks revenge; Saima decides to spy on her brother and uncovers far more than she bargained for.