The Keepers. The Fourth Equation

Games with time do not pass without consequences for anyone. Professor Sharov has learned this from his own experience. In hopes of correcting the mistakes of the past, he resurrected his worst enemy, but this turned out to be just a part of the problems he created. His experiments with time travel accidentally helped a group of Moscow scientists from 2029 create a stable passage to 2006. Now, not only the future of the Zone but also the existence of the world familiar to the professor is at risk. Sharov has no choice but to prove in practice that the Zone did not make him one of the Keepers for nothing.