As shown to Chris Cwej by the Carnival Queen, in its prime this part of the pre-universe was a busy city carved into the side of gigantic ivory tusks that sprouted from the ground in mile high arches. Mechanical spiders spun pathways made of web between the tusks, from which hung gardens tended by stone men. Steam-powered mammoth skeletons roamed the ground beneath the city with scholars and philosophers on their backs. (PROSE: Christmas on a Rational Planet) Original Mammoths, the rulers of the city, created humankind with breeding-engines in one of the ivory palaces. (PROSE: Cobweb and Ivory) While this city was thought to be lost with the rest of the pre-universe when the Time Lords created history, (PROSE: Christmas on a Rational Planet) some of its towers survived in the alter-time realm amid a dark void.
Avus discovered the alter-time realm and journeyed into it. Walking along the silk pathways, he tried to enter six ivory palaces. The seventh palace was open and in it he found an army of painted warriors, (PROSE: Cobweb and Ivory) the old gardeners of the city. (PROSE: Christmas on a Rational Planet) The warriors chased Avus through another palace, where he saw an abandoned breeding-engine with an unformed human child, and towards a great temple. In a park before the palace, Avus fell into a pool of praxis below an onyx tree. Under the influence of the drug, Avus was used by Cernunnos as a conduit into the alter-time realm. The warriors pulled Avus out of the pool and brought him before Cernunnos on a gold and ivory throne in the temple. Avus then escaped to the Homeworld through a weakness in Cernunnos' mind.