Beneath Karak Azgal

From the introduction: Ironbeard has a problem. Actually, his whole family has had a problem - for decades now. It all started with his father Grimcrag, who went into the ancient tunnels near Karak Azgal. Grimcrag knew some dark evil was lurking in the tunnels, but could not identify the source. He made a deal with the local elves to borrow a powerful icon of holiness called the Star of the Dawn. In exchange, he gave them the Gunnarson family Book of Deeds.