The Key (S04E07)

A case that Jeffries worked on when he was a rookie in 1979 is reopened when evidence is found near the original location of the female victim's body. Jeffries made a promise to the woman's daughter to find her mother's killer and now, armed with new evidence, he is more determined than ever to close the case and bring the murderer to justice. The evidence includes a jacket belonging to the victim and car keys that could not have been hers, because she did not know how to drive. Among the suspects are the victim's husband, her ex-lover and her daughter. Now, Jeffries must go back 27 years and retrace his steps - but as a more experienced detective. (Warner Bros. UK)