Detective Superintendent Stella Gibson is brought in from the London Metropolitan Police to help catch the killer when a murder in Belfast remains unsolved.
As Gibson travels across from London, we are introduced to the murderer himself; Paul Spector.
When a Belfast murder remains unsolved, Stella Gibson is brought in to catch the killer.
DSI Stella Gibson's fears are realised as Spector's murder spree in Belfast continues.
As DSI Stella Gibson takes control of the hunt for the serial killer striking women in Belfast, the realisation that his perfect kill is tainted pushes Spector into looking for his next victim.
When Eastwood's investigation into Olson's murder throws open some uncomfortable truths for Burns, Gibson comes under increased pressure in her hunt for Belfast's killer.
Gibson arrives at the Annie Brawley crime scene and realises it is the work of the serial killer, while Burns and his team are still trying to piece together the events surrounding Olson's murder. Spector raises Sally Ann's suspicions when he asks her to provide him with an alibi and he decides to make one final play with Gibson that will bring the two hunters closer than either could have previously imagined