On the verge of failure, Soviet intelligence officer, state security colonel Ivan Grigorievich Koval, is forced to urgently leave the United States, where he spent many years, and return to a country that has become different. Finding himself unclaimed, he retires and decides to spend the rest of his days in the small Ukrainian town of Prikordonnoye, where he was born and raised. Here Colonel Koval unexpectedly encounters a former colleague from a past life - an officer of the Pentagon Research Center, Major Pint, associated with the development of biological weapons in American secret laboratories. Ivan Grigorievich alone enters into a dangerous battle with a seasoned foreign spy...