Apparently, the relatively calm life of Earth’s people is coming to an end: it turns out they live side by side with mysterious beings. But who are they—parasites? Symbiotes? It depends on a small group of scientists, who—against their will—found themselves at the center of this problem, what will happen to our civilization: will it fall into the horror of a battle with an unknown enemy, or will it find the strength and reason to penetrate the essence of things?