This was probably Robert Siodmak's first Hollywood feature, and it's an amazing picture full of innovations and surprises, the action never stops but constantly goes on in a frantic pace, and the ingenious story is overspiced with splendid good humour. It's a very dark noir indeed, a theme typical of Hitchcock's most exciting thrillers, and only the beginning sets you off att rocket speed into action, as a highstrung victim of some sort escapes from a mental asylum, runs into a doctor, stays with him and gets murdered at his place, while the doctor is convicted for the murder. The rest is a romantic nonstop escape together with a beautiful woman, an artist, who begins by betraying him... Robert Donat and Robert Cummings made many such roles, but here it is Richard Carlson together with Nancy Kelly.
When at last they find the real professor and he is brought to explain what the plot is all about, this results in a most unexpected high gear finale, worthy of Hitchcock's best. I loved this film, a rare treat, and a splendid entrance for Siodmak into Hollywood.