Robert Jackson is convicted of murdering five women. A day later, another woman is killed in a similarly brutal manner. The detectives fall under pressure when questions arise about how Jackson had managed to slip through the police's net.

The team investigates whether the latest murder was a revenge killing, a challenge to the police, or a copycat. Meanwhile, Mowbray and Henderson face their own court trial, and the detective has to decide whom he can trust.

The investigation into the most recent murder brings about unforeseen consequences in high places. Cracks also begin to emerge in the case against Robert Jackson when Mowbray learns that crucial evidence had been suppressed.

Jackson is released from prison and seeks to cash in on his celebrity, while the detectives have to sift through all the old evidence again. Finally, they get a breakthrough--a link between the latest killing and one of the Welsh murders.

Henderson realizes the killer has to be someone they all know. As Mowbray closes in on a suspect, he alerts his family to the danger. In the end, it's a race to see who can get to their target first.