The Osh sector of the Moscow border detachment in the Pyandzh direction. The garrison commander, Colonel Buryakin, receives a directive from Moscow to allocate an escort for a limited contingent of Soviet troops crossing into Afghanistan in the winter of 1979. Two young officers refuse to carry out the order and are forced to demobilize because of it. But in 1984, on the same stretch of border, one of the secret patrols catches a violator. He turns out to be one of those officers. During interrogation it emerges that he was heading to the area of the high-mountain lake Kara-Su โ "Black Water," where on an island in the middle of the lake there was a camp for especially dangerous prisoners, one of whom was allegedly ninety-year-old Rudolf Hess, one of the creators of the Third Reich!