Holmes and Watson board a passenger train bound from London to Edinburgh, to guard the Star of Rhodesia, an enormous diamond worth a fortune belonging to an elderly woman of wealth; but within the first hour of the trip, the woman's son is murdered and the diamond stolen and any of the passengers in their car could be the killer thief.
Basil Rathbone
Nigel Bruce
Alan Mowbray
Dennis Hoey
Renee Godfrey
Frederick Worlock
Mary Forbes
Skelton Knaggs
Billy Bevan
Geoffrey Steele
Janet Murdoch
Gerald Hamer
Leyland Hodgson
Harry Cording
Charles Knight
Boyd Davis
Bobby Wissler
Gilbert Allen
C. Aubrey Smith