A small time diamond merchant jumps at the chance to supervise the purchase and cutting of a large first class diamond. But when the diamond is stolen from him, he is blackmailed into pulling off a major heist at the Diamond Exchange, located at 11 Harrowhouse.
Charles Grodin
as Howard R. Chesser
Candice Bergen
as Maren Shirell
James Mason
as Charles D. Watts
Trevor Howard
as Clyde Massey
John Gielgud
as Meecham
Helen Cherry
as Lady Anne Bolding
Peter Vaughan
as Coglin
Cyril Shaps
as Wildenstein
Leon Greene
as Max Toland
Jack Watson
as Miller
Jack Watling
as Fitzmaurice
Clive Morton
as Sir Harold
