A dark and mysterious house, a handcuffed corpse, a stolen necklace, a band of criminals, a prowling detective and a female crook who falls for him: these are the main whodunit ingredients of this early Hitchcock thriller, which turns in the second half into one of the most extraordinary of Hitchcock chases.

“All of the energy pent up in the convoluted conventions of the whodunit form is released in the second part of the film: a wild race across the English countryside between a freight train and an abducted tour bus that climaxes with the locomotive, tender, and car after car smashing onto a cross-channel ferry.... Raymond Durgnat has called (the) climax ‘one of the most sustained, varied and exhilarating disasters in movies,' and Hitchcock's achievement is all the more remarkable when we consider that his low budget obliged him to make extensive use of miniature models for his effects.”