Auzou Livre pour la nuit des dragons tome 3 le dernier combat

While Ervaël is turned to stone by the master of scales' Machiavellian plans, Ourana is determined to save his mentor. He sets off in search of the Jewel of Harmony, which lies at the heart of La Fournaise, the most dangerous of volcanoes... Alone, the dragon will have to face the greatest enemy dragons has ever known.