The plot is thick, and it is difficult to follow all the twists and turns of this intricate concoction of the purposed perfect murder. Margaret Lockwood is perfect as the nurse under suspicion, since more than one patient of hers happens to die of poisoning. Fortunately she has a young alert attorney for her defense who sees through the web of intrigue and finally dispels it. This is typical for Sidney Gilliat's thriller construction with many difficult threads to follow through to an end which no one could have any idea of. The dialog is intensive, intelligent and sharp all through, and inspector Roger Livesey is too straight forward to be able to be fooled or to not commit mistakes. The combination of Gilliat's mastership in script writing with Carol Reed's equally masterful direction makes this film a gem among British thrillers of the 30s. We don't often see Carol Reed conduct a trial and least of all in a murder case, but he handles it expertly only by directing the human hands without any unnecessary dramatic action. This film deserves to be watched more than once, and each time you will find new values in it.