They may have handed in their badges and collected their pensions years ago, but Lane, Standing and Halford are back for a third series, still working at the London Metropolitan Police as civilians investigating unsolved crimes as part of boss Pullman's team, Unsolved Crime and Open Case Squad (UCOS). In this third series, the team have more to worry about than just fire and brimstone when they investigate the chilling death of a member of a witches' coven. Did black magic play a part in the murder? In the office, things get personal when Halford discovers the truth behind his wife's death, while Pullman has to decide whether she should apply for promotion - and leave the team.