The PCs investigate the temple. They find that it appears to be four secretly connected temples, each with the same layout consisting of a chapel, priestess's cell, and holy of holies devoted to one of four unknown and alien gods. These rooms and temples connect in geometrically impossible ways, causing mental stress on the explorers, except Onan, who has seen this sort of thing before. They find a number of books (Harbingers, Apocrypha of Lesser Gods, The Godling Made Flesh, Dead Heresies), including a magical one called Rites of Phuathos. At first, the temples seem to be deserted, with no sign even of the will-o-wisps that led them here, but after much exploring they find a dwarven woman with her hands shackled, lying on a bed in one of the priestess's cells.
She's scared, and tries to get the PCs to leave the temple with her. When they detect that she is under the effects of a transmutation, they become suspicious. She is eventually persuaded to reveal her true form, a succubus. They get her to explain something of this temple. She worships the Great One, an old god with many forms. The four temples connect to different places in the world, each meant to appeal to the people who once lived there. Worship for the masks of the Great One have declined at the temple over the centuries, leaving her and her deacons luring innocents here one at a time for sacrifice. She was shackled by her deacon and left here. She tries to convince to PCs to help for seek out her deacon so that the magical shackles can be removed.
The PCs cannot trust a succubus. Combat ensues. She tries to escape, but is killed. In her chamber they find a smooth marble disc with an indentation on one side. The PCs continue to explore and find in one of the holy of holies, in front of a statue of Golathan, and 10 foot wide pit full of humanoid bones. Four dwarven skeletons lie on the sides of this pit. As the PCs go to investigate he skeletons, the will-o-wisps attack. During the fight, Anathra and Sidium are killed and one of the will-o-wisps is destroyed. The remaining three will-o-wisps are destroyed by crushing the skulls of the skeletons they seemed to be protecting.
Varrokh and Onan investigate the skeletons and find they recognize two of the individuals. One is Bjarne's father and the other is Erasmus, the undertaker. It seems that when dwarves go missing into the moors, the don't return afterall. They are instead replaced. Investigating the books, they find that Rites of Phuathos is a book of five forms: one for each Mask of the Great One worshiped at this temple, and the base form, called Masks of the Great One. From this base form they discover that the priestess is served by doppelgangers. They collect the distinctive parts of the skeletons as evidence.
In the book, The Godling Made Flesh, Onan discovers a ritual that can be used to revive their fallen comrades, but which requires an expensive gem. They return to town, and find that Lira believes they assaulted her sister. After explaining to her about the doppelgangers and showing her evidence, she decides they might be able to be trusted afterall.