Major Pronin is the greatest intelligence officer, counterintelligence officer and detective of the twentieth century. He was both the Soviet Sherlock Holmes and James Bond. But in the Khrushchev years of struggle with the consequences of "Stalinism" and "Berievism", the authorities brought charges against him. To justify himself, Ivan Nikolaevich Pronin had to re–conduct the case, going back a quarter of a century ago. And he again managed to expose the spies, saboteurs and their hires who were carrying out subversive work in the Ural mines. Did Pronin violate socialist legality? Perhaps his investigations of the Stalinist years are the fruits of espionage? Each of you will answer this question on your own when you see the panorama of the investigation conducted by the security officer. It is strongly recommended for all fans of adventure literature to read.