One of the more realistic as well as honest post WWII movies about the threat of Communism simply because it was based on a true story. The film supports the well worn notion of truth being stranger then fiction.
Setting up a number of sleeper cells at the hight of WWII in and around the Canadian City of Ottawa the Soviet Union has developed a spying apparatus that's soon to became the biggest foreign spying network in all of North America. With the head spy a Canadian Communist named John Grubb, Barry Kroeger, having a number of his team of Soviet agents in the Atomic Research Division of the Canadian Government. Glubb and his boss' back in Moscow got wind of a secret project that the US was developing in the use of atomic energy to harness and create an nuclear chain reaction, an Atomic Bomb, that will eventually be use against the axis to end the Second World War.
The movie "The Iron Curtain" has to do with Soviet cypher clerk Igor Gouzenka, Dana Andrews, who being station in Ottawa becomes very disenchanted with his country of birth, the Soviet Union, and decides to defect. Igor is hampered with the fact that he has family back in the USSR and a wife and young child Anna & Andrei, Gene Tierney & Robin Olsen, here in Canada where goons from the Soviet NKVD, working for the Soviet Embassy, can easily get their hands on them. We see Igor go through a number of stages during his stay in Canada as he soon realizes what he's missing in not living in a free country and just how hellish his home the USSR really is.
Being a good soldier, or cypher clerk, Igor does his work smoothly and without a flaw until his wife Anna ,who with Soviet Government approval, came over to visit him from the USSR and later gets pregnant with his son. All this changes Igor's feelings about his motherland, Mother Russia, in wanting his son young Andrei to live and grow up free in a free land Canada. What really pushes Igor over the line, and gets him and his wife and son to defect, is when he gets to see his best friend Maj. Semyon Kulin, Eduard Franz, crack up while gulping down a bottle of vodka and spilling his guts out. Maj. Kulin is sorry that he ever got involved with the Bolshevik/Communist regime. Knowing now just how evil it is in it doing in Kulin's his old man a great and proud leader of the 1917 Communist, or October, Revolution has driving him to drink. They, or Uncle Joe Stalin and his gang of murderous cutthroats, felt that Kulin's father was no longer useful to them and their cause in taking over, by extreme and brutal force if necessary, the both civilized and uncivilized world and thus kicked him out of power. The old and sick guy is now left to live on his meager pension in a one room walk-up, with pop suffering from a case of sever arthritis, apartment in Moscow.
It took a lot for Igor to do what he did in going over to the other side and not only revealing what he and his cohorts, both Russian and Canadians, were up to. Igor also stole from the Soviet Embassy over 100 pages of documents revealing the Soviets plan to steal the secret of the Atomic Bomb that Igor was terrified that they, the Stalin gangsters, would use to blackmail and thus take over, by hook or by crook, the free and none-Communist world.
Igor gets away from the Soviet Secret Police, the dreaded NKVD, only because their so clumsy and confused in operating in a free, unlike their home turf the USSR, and open society. Igor then had, after almost being handed over to his countrymen by a bunch of brainless and clueless Canadian bureaucrats, himself and his wife and son, Anna & Andrei,given political asylum. Igor Gouzenka died in his adopted country Canada on June 28, 1982 at the age of 63.
The vengeful Soviet Union who had put a price on his head and had dozens of secret agents looking to both find and do Igor in had him wearing a musty and smelly hood over his head in public to keep from being recognized and assassinated. This was a small price for Igor to pay to be a free man in a free land which he wasn't back home in the USSR.
P.S The famous statement "Iron Curtain" that's been attributed to Winston Churchills speech in Fulton Missouri on March 5, 1946 was actually coined by non-other then Nazi Propaganda and Culture Minister Dr. Joesph Goebbels a year earlier in an article that he wrote for the German newspaper Das Reich. Goebbels statement was broadcast by the British BBC, on Feberuary 25, 1945 in the waning weeks of the Second World War in Europe. A broadcast that Churchill obviously heard and later used Goebbels timely phrase "Eis Erner Vorhang", the Iron Curtain in German, in his Fulton speech.