The Vanished Moon Event was a subplot of the Eternal Night Saga.
When Tavarius manipulated the Disc of the Nocturne to create the Eternal Night, all signs of the Goddess Ourania vanished. The moon could not be found in the heavens, and Her reassuring voice failed to respond to the searching cries of Her faithful. Icy dread gripped the Order of the Moon and those within the city of Hashan who relied on Her guidance.
The net and the Nychtaur
After several months of fruitless searching, the Order was seen to gather at the ocean cliff near Tasur'ke, a place sacred to the Goddess. The focus of their attention soon became obvious; the three visages of their Lady stood at the entrance of the temple, weaving as they chanted a mysterious poem. When their work was completed, they crumbled to dust, leaving only a shimmering net of stars and their riddle.
The Order realised that, in order to empower the net, its members would need to find the moon. They soon flew to work, racing about the continent, seeking to find a way to perform this command. Finally, it was discovered that though the moon had vanished from the sky, its reflection was still preserved in the waters of the six cities. Moving quickly to each one in turn, the Order spread the net across the water, and was rewarded to see it shimmer with power as it absorbed the moonlight.
Having been empowered at all six cities, the net was taken, in accordance with the riddle, to the Nychtaur, which was busily ravaging New Thera. The Spirit Walker Kaixis hurled the net over the beast, and all were astonished to see it transform into a mighty nightmare stallion. Further astonishment occurred to those watching when, suddenly, Thoth and Valnurana appeared. Neither of these Gods had been seen by mortals in many years. They swiftly discussed an old agreement between Themselves, and then departed. Valnurana took with Her the nightmare stallion and the herd of lesser nightmares that had been wandering the land during the eclipse.
The white bat
Though there was general relief at the departure of the Nychtaur, Ourania was still missing. To add further worry, the Order had begun to be assaulted by visions of a horrible white bat tormenting a sleeping Goddess. Going to Ourania's daughter, Kastalia, Goddess of Lakes and Rivers, they begged Her to aid Her mother. The Goddess agreed, and set off on a journey into unknown planes.
While Kastalia was searching, a white bat was spotted in the area of Tasur'ke. The bat inexplicably remained in the Garden of Whispers, particularly around the Garden of Moonlight, attacking and chasing Ouranians on sight. Determining it a possible source of their troubles, the Order imprisoned the bat in a cage. Within its confines, the bat boasted of its triumph over their Goddess and spoke in grand terms of its master's power.
Failure of Slith's plan
By this point, Tavarius had been revealed to be Slith by the Mitran ritual headed by Aerilius, so there was little doubt as to the identity of the creature's master. It was clear that Slith, probably with the aid of Isillinde, had made arrangements to prevent the Goddess from reacting to his interference with Her realm.
It became evident that Slith's concern was justified. Though caught by the power of the great bat, the Goddess's final effort had resulted in the creation of the magical net. Not only did this enchantment subdue the Nychtaur, but it also served as the bridle by which the pregnant nightmare could be led to safety. It was the offspring of that nightmare, a unicorn, that ultimately shattered the ward of power and foiled Slith's plans.
After a few more months of waiting, Kastalia returned, bearing Her unconscious mother in Her arms. Both relieved and alarmed, the Order quickly had the Goddess placed deep in the safety of the inner temple, there to peacefully sleep out the remainder of the eclipse. Shortly after the night was lifted, the visages returned and the Goddess awakened.