Nuclear physicist Gedimin Ket, after a long, difficult project in the crazy world of the Plain, returns to Earth - and discovers that his home world of Tlakanta, the further away, the less different it is from the Plain. Hordes of alien creatures are fighting with the space fleet, hundreds of shelters are hastily built underground, more and more strange creatures are coming into contact - and they, it seems, are not very friendly to earthlings. The membrane separating the worlds is finally losing stability, and irrencium, once considered just another radioactive metal, is very purposefully pulling its “roots” to the Earth’s core, changing properties as it goes. Someday Gedimin will call this phenomenon the “Tlakanta syndrome” - but by that time there will be neither Tlakanta nor the Earth...