Thirteen-year-old Nick and his slightly dense older brother Herbert run the Diamond Private Detective Agency above Camden Town Tube Station in north-central London. When a master criminal called The Falcon dies, they come into possession of his box of chocolate Maltesers, which contains the secret key to a fabulous cache of diamonds. Can they unravel the mystery and avoid the clutches of seedy lowlifes Brenda Von Falkenberg, Gott and Himmell, The Fat Man and the dogmatic Chief Inspector Snape, all of whom want to find the swag first.
as Nick Diamond
as Tim Diamond
as Lauren Bacardi
as Mr. Patel
as Betty Charlady/Brenda von Falkenberg
as Boyle
as Jack Splendide
as Chief Inspector Snape
as The Fat Man
as Gott
as Himmell
as The Professor
as Henry von Falkenberg
as Johnny Naples (as Rene Ruiz)
as Lawrence
as Hammett
as Vicar
as Bouncer
as Club Owner
as Traffic Warden
as Large Woman
as Sales Girl
as Sales Girl
as Perturbed Mother
as Grandfather
as Granddaughter
as Uncle Holly
as Harpoon Salesman
as Fat Man's Henchman
as Fatman's Henchman
as Fatman's Henchman
as Fatman's Henchman
as Fatman's Hnechman
as Dog Walker