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.

As Mowbray and Henderson head for trial, it appears that someone has been providing the prosecution with inside information. A senior police officer advises Mowbray to place truth over loyalty in the courtroom. Outside the courtroom, the killing continues.

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.