The fertile planet Pern, inhabited in ancient times by terrestrial colonists, is subject to regular disasters - invasions from space threadlike spores that destroy any organic matter. The inhabitants of the planet, who have forgotten the technical achievements of their ancestors, escape from the threat in stone cities - holding houses But the main means of protection are powerful, noble dragons, semi-intelligent creatures, whose fiery breath burns deadly spores. However, only gifted telepathic people can understand dragons and only they, the Horsemen, can save the beautiful Pern. But here come the times when there are almost no Horsemen or dragons on the planet... Times when the terrible Threads reappeared in the defenseless skies of Pern.