The reign of dinosaurs comes to an abrupt end for reasons unknown. Some claim it was a meteor, others believe it was climate change or a virus of some kind. The real cause lies in the formation of the Realm of Mithbar and its position between Earth and the Inner Realms. As the new Realm is formed, parts of Earth are accidentally transported to it. Several dinosaurs and insects are among them, along with a limited number of mammals and other living organisms. The various species of flora form the basis for the Realm's future vegetation.