Artur Ludvik, alias Gerard, is a loyal communist and hero of WWII who serves as the vice-minister of Foreign Affairs of Czechoslovakia in 1951. He realizes he is being watched and followed, and meets to discuss this with a group of his friends who have also attained top government positions. They realize they are all being watched, even the chief of the same secret police force that is carrying out the surveillance. One day, Artur is arrested and jailed by an organization that declares itself "above the ruling party", and put in solitary confinement for months without being told the reason why. His wife Lise and their children are kept in the dark by the government and told to cooperate for their own good; Lise is later removed from her job as a prominent radio news announcer and forced to work in a factory by the party. Though she believes in her husband, she is equally certain in the wisdom and ultimate goodness of the party. Through brainwashing techniques, including sleep deprivation and being forced to walk back and forthall the time, Artur is slowly pressured into confessing imaginary crimes, including treason, and baited with the prospect of leniency at sentencing if he cooperates. He also learns that his friends have been arrested as well and are implicating him in crimes against the state. Upon finally confessing to his alleged crimes, Artur is then groomed for a public "trial", which will be broadcast live on radio and shown in cinemas. While his captors coach him to memorize prepared answers by rote, he is given robust meals, vitamin injections, and a sunlamp to improve his appearance after years of wasting. At the trial, Artur and his colleagues faithfully play their parts. Lise, to her shame, is forced to make a recorded statement disavowing her husband and praising the party which airs during the trial. The prisoners are variously sentenced to either death or life imprisonment, with Artur given the latter. When their interrogators do not return to them, the prisoners panic and threaten to appeal, but are told by their court-appointed lawyers that the sentences are only for the party's benefit and will not be enforced if they do not appeal. The convicted men appear in court one final time to accept their sentences and waive their right to appeal. Afterwards, Artur and some of his colleagues are gradually freed and rehabilitated between 1956 and 1963. However, the rest are executed and cremated, with their ashes scattered along a road. At the same time, a number of the officials behind the ordeal end up facing their own persecutions, including Kohoutek, Artur's own interrogator. Artur later encounters the demoted Kohoutek, who tries to downplay his role in Artur's torment by claiming he was only following orders and never understood what the party wanted. In 1968, Artur completes his memoirs of his experiences in captivity and returns to Czechoslovakia to have them published. By then, amidst the Prague Spring, the reactionary elements who had orchestrated the entire affair had been pushed out of power by the party, and Artur believed that the party now desired to expose the truth of what happened during those years as much as Artur himself did. Unfortunately, he arrives in Prague just as the Warsaw Pact invasion of Czechoslovakia begins.
Yves Montand lost more than to play his role. Montand had been shaken by the 1956 events in Hungary and later said of the film: "There was in what I inflicted upon myself something of an act of expiation."
