DS Steve Arnott is arrested on suspicion of murder but continues to protest his innocence.

Loyalties are divided when DS Steve Arnott comes under scrutiny from his colleagues.

Sergeant Danny Waldron and his armed response team shoot dead a hardened criminal.

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

Fresh testimony launches AC-12 back on the trail of a corrupt officer.

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