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.

Evidence against Denton begins to mount, but she won't go down without a fight. The increasingly erratic detective begins to uncover past actions that put her investigators-DS Arnott, DC Fleming, and Superintendent Hastings-on the defensive.

Lindsay is denied bail and finds herself targeted in prison. Growing increasingly desperate, she reveals her relationship with an executive police officer to Kate and her theory of why she is being framed.

Denton alleges a high-level conspiracy and cover-up. Only when she is granted special dispensation to leave prison to visit her dying mother do Arnott and Fleming begin to realize the danger she is in.

While Denton fights for her life, details emerge of her relationship with a senior police officer. Hastings faces the prospect of having to confront a superior who holds the superintendent's future in his hands.

AC-12's investigation finally exposes a vicious criminal gang run from within the police. But while Steve now appears convinced of Lindsay's innocence, Kate remains determined to prove she had a role in the ambush.