During World War II, after the Soviet invasion of Poland, young Polish army officer Janusz Wieszczek (Jim Sturgess) is held as a POW and interrogated by the NKVD. The Soviets, unable to get him to admit that he is a spy, take his wife into custody; from her they extort a statement condemning him. He is sentenced to 20 years in a Gulag labour camp deep in Siberia.