Hawes will play Detective Inspector Lindsay Denton, the sole surviving police officer of an ambushed police convoy in which three colleagues are killed and a protected witness seriously injured.
Deputy Chief Constable Mike Dryden (Robert Lindsay) takes personal charge, assigning AC-12 to the case.
Detective Sergeant Steve Arnott (Martin Compston), Detective Constable Kate Fleming (Vicky McClure) and Superintendent Ted Hastings (Adrian Dunbar) are joined by newly appointed Detective Constable Georgia Trotman (Jessica Raine) to investigate a complex case rich in unexpected twists and turns.
Initially AC-12’s most valuable witness, the suspicion soon arises that DI Denton could be their prime suspect.
Hawes said she was “thrilled” to be joining the series which was BBC Two’s biggest new drama series for 10 years, averaging 4.2 million viewers when it aired last year.
The actress added: “After reading Jed’s incredible scripts I can’t wait to take my character, DI Lindsay Denton, on the epic journey he has created for her. I loved the first series so it’s a real pleasure to be part of series two and working alongside such talented actors like Vicky McClure, Martin Compston and Robert Lindsay.”
Written and exec-produced by Jed Mercurio, the series starts fillming in Belfast later this month.
Mercurio commented: “I was thrilled by the success of series one, and I’m hugely grateful for the opportunity to create another six hours of twists and turns as our returning investigators delve into a brand-new story of police corruption.”