Master criminal Giles Conover (Miles Mander) steals the famous "Borgia Pearl" from the Royal Regent Museum under the very nose of Holmes and Watson, but when caught the pearl is not found on him and he is released.
Later, Holmes hears of an apparently motiveless murder. An elderly colonel is found with his back broken amid a pile of smashed china. Holmes takes an immediate interest in the case as the unusual method of killing is that of "The Hoxton Creeper" (Rondo Hatton), known to be Conover's right-hand man.
Another murder occurs, of a little old lady, also surrounded by smashed china. Conover makes two attempts to kill Holmes, who surmises that Conover is desperately trying to recover the stolen pearl.
After a third killing Holmes finds the common feature of each: a bust of Napoleon. Conover, when being pursued by the police, had fled through the workshop where they were being made, and hid the pearl inside one of six identical busts.
Holmes tracks down the vendor of the busts and find out that one is still unaccounted for, as does Conover's accomplice Naomi. Conover and The Creeper arrive at the house of the owner of the final bust, only to find that Holmes has taken his place. Overpowered, Holmes convinces The Creeper that Conover will double-cross him, and the Creeper turns on Conover and kills him, after which Holmes kills the Creeper, before the police finally arrive. Holmes smashes the final bust and recovers the pearl "with the blood of five more victims on it".
Cast:
Basil Rathbone as Sherlock Holmes
Nigel Bruce as Dr. John H. Watson
Evelyn Ankers as Naomi Drake
Dennis Hoey as Inspector Lestrade
Miles Mander as Giles Conover
Ian Wolfe as Amos Hodder
Charles Francis as Digby
Holmes Herbert as James Goodram
Richard Nugent as Bates
Mary Gordon as Mrs. Hudson
Rondo Hatton as The Creeper
Wilson Benge as Second Ship's Steward
Billy Bevan as Constable
Harry Cording as George Gelder
Al Ferguson as Security Guard
Colin Kenny as Security Guard
Connie Leon as Ellen Carey
John Merkyl as Doctor Julien Boncourt
Leyland Hodgson as Customs Officer
Lillian Bronson as Harker's Housekeeper
Harold De Becker as Boss
Leslie Denison as Police Sergeant Murdock
J.W. Austin as Police Sergeant Bleeker
Arthur Mulliner as Thomas Sandeford
Arthur Stenning as First Ship's Steward
Eric Wilton as Conover's Chauffeur
Charles Knight as Bearded Man
Audrey Manners as Body of Teacher
