The film is dedicated to the trial of O. V. Penkovsky, accused of espionage for the intelligence services of Great Britain and the United States, and British citizen Greville Wynn, an agent of British and American intelligence. Moscow city. May 1963. The movement of a prison van through the streets of Moscow. Supreme Court building. Court session in the Penkovsky-Wynn case. The chairman of the court V.V.Borisoglebsky, people's assessors - generals S.K.Marasanov, I.S.Tsygankov, state prosecutor General A.G. Gorny, lawyers K.N. Apraksin, N. S. Borovik. The audience in the courtroom. A.G. Gorny is interrogating the accused (synchronously). The accused are answering questions, OV Penkovsky and G. Wynn (synchronously). V. V. Borisoglebsky announces the verdict (synchronously). Materials of the criminal case. Material evidence, including photographs, filming. Meeting at the airport in Moscow, wife of G. Wynn Sheila Wynn, who arrived at the trial. American attache R. Langelli, wife of attache M. Esther walking along the streets of Moscow. Foreign journalists at the telephone sets. G. Cowell, a diplomat deprived of diplomatic immunity, climbs the plane. Fragment of the documentary "Along the Black Path"; US embassy staff on the roof of the embassy building. Photos of diplomats-spies. British Embassy building.