Residents of the town located near the Perimeter are forced to engage in activities that are not customary to talk about. But when the dark spot of the growing Zone begins to spread across the Moscow region, it is the skills of a local stalker named Algorithm that become necessary for a variety of people - and not only people. And the Algorithm also likes to find relationships between seemingly unrelated events. And one day it is this quality that will cause a deadly situation. Together with his random fellow traveler Vera, the hero enters into a confrontation with a mutant from mutants. But are ordinary people able to defeat the one who mutated twice?