Perhaps not one of Hitchcock's most prominent films, but it's a tense crime thriller telling the tale of a family of recent émigrés to Britain who are struggling to run their small London cinema. Oskar Homolka ("Mr. Verloc") falls foul of some criminals who offer to pay him for carrying out an act of sabotage. This doesn't quite cause the mayhem they desire so he is unwittingly, this time, involved a much more deadly action. Unbeknown to him, Scotland Yard are on to them and have planted a detective (John Loder) in the greengrocers who befriends the family. The plot unfolds slowly and tensely....