Dr. Tony Hill (Robson Green) is a clinical psychologist with an extraordinary understanding of the criminal mind. Working alongside Detective Inspector Alex Fielding (Simone Lahbib), Tony must race against time to profile and track down vicious killers before they strike again.

Disc 1: Unnatural Vices
Dr. Tony Hill investigates what appears to be the honor killing of a young Kurdish woman. However, the site where the body was found yields remains of other victims and an even more gruesome motive for the crimes.

Disc 2: Falls the Shadow
After several colleagues are murdered, Tony is arrested as the prime suspect. With time to ponder the ritualistic nature of the attacks, he finally finds a link with several recent prostitute killings.

Disc 3: From the Defeated
Tony becomes absorbed in a bizarre chain of murders in which each perpetrator in turn becomes the next victim, but the unusual modus operandi – always involving the same gun – remains identical.

Disc 4: The Dead Land
A killer starts dumping the bodies of homeless men in the financial district of Bradfield, leaving little evidence behind. Meanwhile, Tony fails to foresee the threat to his own life from a mysterious stalker.