The Unsolved Crime And Open Case Squad (UCOS) faces a difficult professional and personal dilemma when Brian Lane is forced into rehab (a rehabilitation clinic) to treat his alcoholism and stumbles on a case involving the death of a heroin addict. Following the dramatic climax to series five, Brian is drinking in the last chance saloon as far as his wife, Esther, is concerned. She books him into the Trinity Clinic, an addiction centre run by monks and, blaming UCOS for his decline, she appeals to Detective Superintendent Sandra Pullman for the team to leave him alone to recover. Distrustful of the clinic's methods and dangerously under-occupied, Brian is looking for any kind of distraction. He finds it when a chance remark by Father Bernard about an incident at the clinic nine years ago sets his detective's antennae twitching. Drug addict Robert Smith died in a suspected fall 12 days after arriving at Trinity in 2000. His neck was broken and, despite the clinic's strict ban on substance substitutes, there was methadone in his body. The team has a case, but Pullman has made a promise to Esther and feels honour-bound to leave Brian out of the investigation. Gerry's solution is to go undercover, posing as a sex addict. Believing himself to be an expert in this field, Gerry's apparently inspired plan begins to unravel when the one-to-one sessions with sex therapist Anna Greening get a little too up-close-and-personal for comfort. Despite the air of spiritual calm at the clinic, Robert's death begins to seem anything but accidental. As Brian reluctantly edges closer to confronting his demons, will the clinic reveal its own secrets? Guest Stars: Father Bernard - Richard Wilson One Foot In The Grave, Merlin, Born & Bred. Anna Greening - Faye Ripley Cold Feet, Reggie Perrin.