In an ordinary industrial Soviet town, notable only for presence of a radio-telescope, people start behaving strangely, in a robotic manner, while assuming geometry-inspired aliases and organizing into a new hierarchy. The phenomenon spreads via a device of alien origin, called “the mediator”, capable of implanting extraterrestrial minds into human bodies. The aliens are bound by limitations of the terrestrial technology, having to use the means at the disposal of humans to prepare the grounds for the full-scale invasion. With “the mediator" being unable to subdue minds of children, lunatics, geniuses, and rebels, a struggle over the fate of the town and the human civilization ensues.

When a 7-year-old son of the well-known businessman is kidnapped, he has no idea what awaits him! It turns out that the mysterious kidnapper does not need any ransom, but has only one claim: during the next day father must decide who will die of the two: his child or himself...