The film hinges on the love triangle between a young aristocratic lady on the run (Cleonie, played by Hazel Terry), the murderous Varennes, Citizen-Deputy of the Revolution who saves her by disguising her as his nephew (Nils Asther) and finally the Marquis of Corbal of the film's title, played by Hugh Sinclair.
At the height of the French revolution an enforcer, Nils Asther, is sent to a rural village - complete with his mobile guillotine - to despatch an aristocrat who has considerable popular support amongst his fellow "citizens". Hugh Sinclair ("the Marquis") makes no effort to sound French, nor does Hazel Terry as Asther's love interest (whom he has rescued from the head-chopper-offer and has had to disguise herself as a boy to avoid identification). It's all procedural costume stuff with wobbly sets, pretty basic dialogue and, of course, a bit of a love triangle at the end. Its been done on tuppence, but is still a watchable little historical romance.