Scotland Yard superintendent, Richard Jury investigates the murder of wealthy bachelor Billy Maples in a shady London motel. He discovers connections between the murder and the distant past through Maples' grandfather, who served as one of Britain's top code breakers during WWII.

"In the latest series outing, The Knowledge, the Scotland Yard detective nearly meets his match in a Baker Street Irregulars-like gang of kids and a homicide case that reaches into east Africa. Robbie Parsons is one of London's finest, a black cab driver who knows every street, every theater, every landmark in the city by heart. In his backseat is a man with a gun in his hand--a man who brazenly committed a crime in front of the Artemis Club, a rarefied...

Jury investigates the death of a young escort who has been murdered behind a local pub. The only witness is the establishment's black cat, who gives neither crook nor clue as to the girl's identity or her killer's.