Soviet colonel Oleg Penkovsky spends the early 1960s passing technical intelligence to MI6 and the CIA while holding one of the most sensitive positions in Soviet military intelligence. This episode, the third in a five-part series on the race for nuclear supremacy, follows what he handed over and why it mattered: details on Soviet missile capabilities that reached Washington and London just as the Cuban missile crisis of 1962 pushed the two superpowers toward war. Archival footage and expert interviews trace his contacts with British and American handlers, the tradecraft used to move documents without detection, and the KGB surveillance that eventually closed in on him. The film moves between Moscow, London, and Washington to show how one officer's access shaped decisions made at the highest levels of both governments during the crisis's tensest days. Penkovsky's exposure and arrest close out the account, framed as the cost of the intelligence he supplied. The focus stays narrow and procedural, on what was passed, how, and to what effect, rather than on broader Cold War context.