Early eighties. At a dacha near Moscow, operatives detain the leading designer of a secret research institute. For a long time, he secretly transferred data about our strategic developments to Western intelligence agencies. During interrogation, it turned out that the detainee was only one link in a complex espionage chain. The main defendant, under the pseudonym Zvonar, works at the main enterprise in Siberia... A KGB task force led by Major Mikhail Koltsov urgently leaves for the site. And immediately faces murder. Under unclear circumstances, the deputy director of that same Siberian enterprise dies. Koltsov is sure: the Beller sensed danger, and this death is the beginning of his agony...