At Natalon's mining camp, Pellar embarks on a secret mission to discover whether the condemned criminals known as the Shunned are stealing coal. But the gifted tracker discovers that a far more treacherous plot is unfolding. A heartless thief named Tenim has realized there is profit to be made from firestone, the volatile mineral that enables the dragons of Pern to burn the lethal Thread out of the sky. When the last remaining firestone mine explodes, a desperate race begins to find a new deposit of the deadly but essential mineral. Sure enough, Tenim has a murderous plan to turn tragedy to his own advantage. Now Pellar and his new friends--the kind and gentle Halla, a child of the Shunned, and Cristov, the son of a corrupt miner--must stop Tenim. If they fail, it will mean the end for Pern and its dragonriders.