Ten years after local Cardiff girl Geraldine's body was found a few days before Christmas, Detective Superintendent Paul Kemp and his team set out to catch the culprit with new groundbreaking forensic science. However, when they get a DNA match to a suspect they must act fast as he is about to be released from Dartmoor Prison.

Exploring the murder of 22-year-old office clerk Teresa de Simone, who was found dead in the back of her car in 1979. Sean Hodgson's confession was one amongst multiple confessions of men which turned out to be hoaxes, however his statement matches unpublished details of the crime scene. Hodgson now hopes new DNA technology will clear his name, after decades in prison and several failed appeals.