In the 1970s, Western special services plan a sabotage operation at a classified site “Sverdlovsk-45,” where components of nuclear weapons are being assembled. A group of militants, posing as tourists, must enter the forbidden zone and set a fire that will lead to the formation of a radioactive cloud over the region. However, the KGB learns about the enemy’s plans. Responsibility for neutralizing the saboteurs is assigned to a unit led by Lieutenant Colonel Vyacheslav Bogdanov. The fighters track down the enemy and prepare to catch the intruders in the area of Nizhny Tagil. Suddenly it turns out that the spies are being helped by someone from the staff of the secret facility—which completely changes the situation. Bogdanov realizes the need to urgently adjust the operation plan. This novel describes the tense work of specialists from a special KGB unit—from developing a covert operation to confronting a cunning enemy anywhere in the world, a path possible only for brave, devoted professionals.