One of the few "Inspector Hornleigh" films to gain a wide US distribution, it stars Gordon Harker as Hornleigh and Alastair Sim as his dumb-like-a-fox assistant Sergeant Bingham. Borrowing a bit from the 1939 British box-office hit Night Train, the plot pits Hornleigh and Bingham against a clever gang of Nazi espionage agents. Most of the action takes place aboard a speeding train, with our heroes never quite certain who can be trusted and who can't. Phyllis Calvert contributes to the intrigue as one Mrs. Wilkinson, who is, as the phrase goes, not all she seems to be. With Walter Forde in the director's chair, it shouldn't be surprising that it contains as many laughs as thrills.