The OAP detectives return to investigate a fresh batch of unsolved crimes, beginning with the murder of a palaeontologist at the Natural History Museum. After a bit of digging, the team discover the victim was a respected but outspoken scientist with a knack for rubbing people up the wrong way - and when they discover he was strongly opposed to the museum's sponsorship deal with a large fuel company, the old dogs soon have plenty of suspects.

Amanda Redman stars, with guest appearances from the late Trevor Bannister (Are You Being Served?), Lucy Brown (Primeval) and Natasha Little (Spooks)