A group of private researchers discovers a mysterious structure of obviously artificial origin on the planet Jonna. This is another trace of the Harbingers - a certain powerful civilization that visited this part of the Universe millions of years ago. Such artifacts are an invaluable source of information - the main currency among intelligent inhabitants of space - for the possession of which both influential Houses owning Earth's colonies and alien races competing with earthlings compete. At the same time, in another part of the Universe, on one of the planets of the giant star system, an automatic Harbinger base was discovered. It is this that becomes the cause of the conflict between earthlings and the civilization of the Suzayans - a conflict that threatens to develop into a protracted space war.