Five friends - Yura, Jules, Lika, Krest and Kostya - notice that their classmates, seemingly unrelated to each other, are steadily disappearing. The teachers attribute this to the sudden decision of their parents to move to another city. Parents do not pay attention to this, assuming that the child is simply seriously ill and is in the local hospital. But these explanations do not seem plausible to the guys, and they decide to initiate their own investigation.