In 1983, in a village outside Leicester, Lynda Mann is found raped and strangled to death. A year on, after an exhaustive but fruitless search for the killer, DCS David Baker is forced to scale down the investigation.
In a storm of publicity, the local teenager's released and the world's introduced to the idea of forensic DNA. But in the villages of Narborough and Enderby there's a real sense of fear: there's a murderer in their midst.
Possessing what they believe to be the killer's genetic "fingerprint," David and Alec initiate the world's first "DNA manhunt." But as thousands of samples are tested and costs continue to rise, David worries the operation will be shut down before they can find the killer.