When Steve Arnott is transferred to a police anti-corruption unit, he finds his target is the city's top detective, Tony Gates. Can Gates really be as good as he appears? Arnott must engage in a cat-and-mouse struggle to uncover Gates' secret.

The episode was rated 7.61 from 1860 votes.

Arnott is convinced Gates played a part in Jackie's disappearance. With Fleming's help, the anti-corruption team tries to trap Gates into revealing his involvement in covering up Jackie's crimes.

The episode was rated 7.69 from 1549 votes.

Having been duped into covering up Jackie's crime, Gates is desperate to sever ties with her. But, as Arnott and Fleming close in on his secret, Gates is plunged into an even more dangerous situation than he first thought.

The episode was rated 7.77 from 1620 votes.

After the shooting at the drugs house, DC Fleming increases the pressure on Danny Waldron.

The episode was rated 7.81 from 1553 votes.

Lindsay is denied bail and finds herself targeted in prison.

The episode was rated 7.86 from 1375 votes.

Desperate for proof of Gates's corruption, Fleming pushes her relationship with him to the limit. But her behaviour causes Morton to question if she might not be such a loyal colleague after all.

The episode was rated 7.89 from 1516 votes.

AC12's Kate Fleming is planted undercover in Lindsay Denton's Missing Persons Unit.

The episode was rated 7.89 from 1409 votes.

DS Steve Arnott believes there is a dark secret in Danny Waldron's past.

The episode was rated 7.89 from 1517 votes.

AC-12 crank up their investigation into Operation Trapdoor. Kate makes progress in her undercover role.

The episode was rated 7.89 from 1462 votes.

DCI Roz Huntley is under intense pressure from her superiors to apprehend a serial murderer after months of fruitless investigation.

The episode was rated 7.92 from 1583 votes.