The killer's latest attack gives Gibson renewed impetus and as the net appears to be closing in, Spector makes a dramatic confession and a decision that binds his fate to Gibson.
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.
As Gibson takes control of the hunt for the serial killer striking against women in Belfast, the realisation that his perfect kill is tainted pushes Spector into looking for his next victim.
Gibson's worst fears are realised as Spector's murder spree in Belfast continues and a reckless decision has Gibson facing some very real consequences.
DSI Gibson arrives in Belfast to review a murder investigation with the killer still loose.