Peter Lorre returns as the clever and cunning international police detective Mr. Moto in this sixth installment of the popular series. Mr. Moto is on assignment in Egypt's Port Said, determined to thwart a diabolical conspiracy that would destroy diplomatic relations between England and France and jump start World War II. Mercenary saboteurs, led by the paranoid ventriloquist Fabian the Great (Ricardo Cortez) and the duplicitous Eric Norvel (George Sanders), plot to blow up an arriving fleet of French ships. Early on, the evil renegades are convinced they've stopped Mr. Moto for good, but they've actually murdered an imposter! Demonstrating his mastery of disguise, Mr. Moto assumes the identity of a mild-mannered antiques dealer, cannily strategizing against the scoundrels' every move. With the assistance of secret agent Richard Burke (John Carradine), Mr. Moto employs his singular ingenuity to foil the deadly scheme.

One of the last of the Mr. Moto detective series of the 1930's. Lorre plays the Japanese sleuth who tries to outwit saboteurs out to blow up a French fleet at the Suez Canal.