Set in 1960, The Courier begins with Oleg Penkovsky (Merab Ninidze), a Soviet military intelligence colonel, taking an incredibly bold move by secretly telling the American Embassy in Moscow that he is ready to share the United States and Great Military Secrets to betray Britain. Penkovsky, who has no faith in the stability of Russian leader Nikita Khrushchev (Vladimir Chuprikov), fears that the escalating arms race could lead to nuclear war and pledges to provide the CIA and MI6 with all the information he can . The problem, however, is how to physically enable it.