Draga Stonecrusher, Geat Wildhammer, Hestia Crabapple, Rodrigo Castillo, and Harmon of Marryfeld all learn of a public meeting at the Stone Dragon Inn in the town of Mastrop, apparently arranged by the apprentice of the Imperial Court Wizard. Intrigued by the appearance of such an illustrious person in a backwater like Mastrop, they attend
They learn that the meeting is in fact being held by the Imperial Court Wizard, Gazbar, himself. Gazbar is searching for a group of adventurers to accompany him to retrieve an ancient book of magic buried in a lost library under Mastrop. He selects Draga, Geat, Hestia, Rodrigo and Harmon. That night, each of the heroes receives a warning that one of the others will attempt to betray them.
The next day, they descend to the catacombs under the town, where they are ambushed by skeletons. They repel the undead with the help of a litany carved on the wall of the tombs. Later, their way forward is stymied by by a dead end and they are attacked by a zombie. The litany has no effect on the zombie, and the group must kill it. Afterwards, they discover on the corpse plans for the catacombs, including details of a secret passageway. Opening the way, they descend a long dark tunnel, arriving in a beautiful underground city carved from amethyst.
As soon as they arrive, they are taken prisoner by the deep gnomes who live there, but not before Hestia is seriously wounded in an attempt to avoid capture. They manage to escape their prison cell when Harmon uses his magic to charm their guard into setting them free. Killing and subduing the other guards, they flee from the gnome army, and make their way across the city, but Draga is lost in the helter-skelter of the chase..
The party argues over whether they should go back, but Gazbar and Hestia convince the others that Draga has been behaving suspiciously, and she may have been plotting to betray them. They decide to leave her behind. They are surprised then, when after walking through the city for another hour, Draga catches up to them. There are plenty of recriminations about betrayal and abandonment, but they decide to continue forward together. They reach the Library Gazbar spoke of and solve a puzzle trap preventing their entrance. Gazbar performs some extremely powerful magic to open the final door, where they discover he is but the thrall to an even more powerful entity. This entity explains that the whole journey was a job interview to test their skills, which they have passed. The monster offers them a job.