A dead girl lies on a blood-soaked mattress, her limbs spread in a parody of ecstasy. The scene matches a series of murders which ended with the conviction of Derek Tyler. But Tyler's been locked up in a mental institution for two years, barely speaking a word. Criminal psychologist Dr Tony Hill thinks this is not a copycat murder but something much stranger. Hill heads towards a terrifying face-off with one of the most perverse killers he has ever encountered…