DI Alex Drake is taken hostage and shot, and wakes up in a brothel... in 1981. Rescued in a police raid, she quickly recognises DCI Gene Hunt and his team from detailed reports made by DCI Sam Tyler about his own trip to 1973.

Gene is determined to address London's growing drugs problem, and has targeted city playboy Edward Markham as the brains behind the operation. Alex suspects Arthur Layton, the man who kidnapped her in 2008. Could Layton be the key to her return to her own time?