A blood-stained bust is uncovered during some reconstruction work in a cemetery, pointing UCOS to the murder of an alternative medicine practitioner bludgeoned to death seven years ago. The evidence leads to the pioneering but controversial world of cryopreservation - the practice of keeping clinically dead patients frozen in time to extend their lives.
In a sensitive case, with the watchful eyes of their bosses upon them, Sasha is determined that her team won't put a foot wrong. But with suspects constantly running rings around them and the sobering possibility that two perpetrators are still at large, UCOS must go out on a limb to unlock their most difficult cold case yet.
Fiona is offered a job too good to be true in Aberdeen, leaving Danny bereft at the thought of losing her. Ted is devastated when he realises he's lost his lucky cigarette case, and Sasha has an interesting offer from the notoriously cut-throat assistant commissioner Cynthia Kline.
Aired: 29 Sep 2015