Very much in the vein of Carol Reed's similar cold war thriller "The Third Man" (1949), this is a gritty and characterful story set in Berlin just before the Soviet Union imposed travel restrictions. This time, the Communists kidnap "Susanne" (Claire Bloom) - she happens to be the sister of British officer "Martin" (Geoffrey Toone) and we are now presented with an intriguing and internecine series of spy and counter-spy scenarios that revolve around the dubious "Ivo" (James Mason) with whom the missing woman had been associating with - and has fallen for. It transpires that she is being held so that they can use her as leverage for the return of "Kastner" (Ernst Schröder), a lawyer with a distinctly dodgy pre-war past. It now falls to "Ivo" to rescue her and smuggle her to safety. Desmond Dickinson's dark and eery photography - especially in what's left of the heavily bombed out Berlin - coupled with a seedy and effective John Addison score work well to create an atmospheric environment. I didn't love Mason's rather unreliable German accent, but Bloom is quite effective and there are compensating and strong supporting contributions from an on-form Hildegard Knef ("Bettina") and from Aribert Wäscher as the untrustworthy "Halendar" as the plot twists and turns towards quite a menacing and tightly shot denouement. The narrative is tight, the romance sparing, it is frequently quite compelling to watch and it does have a ring of plausibility to it. A superior crime drama well worth a watch.