Line of Duty

After a police convoy is ambushed, the investigation centers on DI Lindsay Denton, the sole survivor. Why did Denton allow a police convoy to proceed without backup and without firearms? Why take the route she did? How did the ambushers know? Denton quickly goes from valuable witness to prime suspect.

Following the tragedy at the hospital, Kate Fleming goes undercover in Denton's Missing Persons Unit.

Denied bail and targeted in prison, a desperate DI Denton tells Kate her theory of why she is being framed.

DI Denton suffers a violent attack in prison and Deputy Chief Constable Dryden shrugs off the allegations against him.

Lindsay fights for her life against troubling details of a vicious conspiracy while Hastings comes under pressure to arrest his senior officer.

AC-12 close in on their targets and Steve appears convinced of Lindsay Denton's innocence, but Kate is determined to prove that she had a role in the ambush.