All seems well on Pern until a mysterious ailment strikes killing myriads of holders, craftsmen, and dragonriders. Pern is left in mortal danger with no one to rise to char the parasitic Thread.
When the last firestone mine explodes, Tenim contrives to turn this tragedy to his own advantage. Only Pellar, Halla and Cristov can stop him, and secure a future for the Dragonriders.
A new chapter in the popular "Pern" series finds the planet's inhabitants threatened by a band of renegades that attempts to expose them to deadly airborne spores in the atmosphere.