From publisher blurb:
An Into the Wintery Gale Mini-Dungeon adventure for four to six PCs of levels 13-14.
This mini-dungeon is intended for use with the Into the Wintery Gale: Wrath of the Jötunn Adventure Path, but may also be run as a standalone quest.
In this encounter the adventurers have met the Hvíturiddare “White Riders” clan of Vikmordere and witnessed their unusual practice of riding into battle on the backs of gargantuan winter wyrms. When the party earns the trust of the White Riders, the clan reveals to them that only very special wyrms can become mounts, and even then only with the use of wyrmreins. These particular creatures only appear within an ancient holy shrine located in the northern mountains—a sacred place known to them as the “Ormurhellinum.”