Originally released in England as simply The Diamond, this fast-paced melodrama stars Dennis O'Keefe as an American federal agent, assigned to the London beat. On the trail of the gang who robbed a US Treasury vault, O'Keefe works shoulder-to-shoulder with Scotland Yard inspector Philip Friend. It develops that the gang is in a cahoots with a London mob, who plan to pay off the treasury thieves with synthetic diamonds. Most of Diamond Wizard is fluent exposition; the big thrills arrive in the final two reels, when the crooks fall out. Margaret Sheridan costars as O'Keefe's American girlfriend.
by Hal Erickson synopsis