First, an accident occurred that killed a person. Then came a suicide. After that—murder. In any other place, all of this would be terrifying. But aboard an international space station, these incidents look simply horrifying. Who among the nine inhabitants of the station is the killer? Everyone is suspected. And yet the mysterious murderer puts forward his demands to the presidents of Russia and America, promising that if they don’t comply, he will kill one by one the station’s residents. And immediately he proves that his threats are not a joke…