In the near future the so called Spirits appeared in the human society. Those were scientists and prophets that significantly influenced technological progress.
One of the main "gifts" the Spirits possessed were the Corridors, portals to other worlds. Those were not planets in the regular meaning of this word. Those worlds existed in another dimension but people could live there.
An active human expansion to those worlds began. These worlds were named the sponge-space because of the theory that dominated in that time. According to the theory the structure of this dimension looks like a sponge with different worlds-cavities. Mankind has acquired the ability to travel between these worlds.
It turned out to be that sponge-worlds weren't just empty lifeless places. They had a connection to Earth. During the whole Earth's history they soaked in all human mental energy, all human emotions and thoughts. All these processes influenced the sponge-worlds' relief. Imprints of human culture, thoughts of many mankind' generations found their place in those worlds.
Sponge-space that surrounded Earth was called the Psychosphere. An assumption was made that mankind could travel to distant planets avoiding space flights. A new mass religious movement has emerged. Members of the movement popularized the idea of a mass exodus from Earth that stuck in sin, passions and political wars. Spirits were active participants of the movement.
A great Crisis broke out on Earth. The cause for it was the developing of the Psychosphere. It turned out to be that sponge-worlds react to human presence and give material form to subconscious fears of people. Earth's space around the Corridors started to become infected rapidly. A decision was carried out to destroy all the portals in 24 hours. However a large group of Exodus movement followers had enough time to leave Earth. Besides a lot of Psychosphere explorers didn't manage to escape back to Earth.
People found themselves face-to-face with hostile worlds. They had to start inventing necessary technologies to survive. Such energy resources as the terraformed zero-level and energy domes became essential for mankind survival. Soon a decision to make Exodus a reality was carried out. A few hundred thousand people decided to start their journey to the Promised Land, a new big world. But nobody knew where it is and how long will it take to get there.
Huge mobile constructions, Frames, were made for the Exodus. Frames were able to explore new worlds and build Corridors. People could also live inside those constructions. However great changes in the social order were necessary to control these cities because Psychosphere's reaction could destroy the Frames in the twinkling of an eye if mental activity of people inside the Frame exceeded a certain rate.
As a result a totalitarian-religious regime was formed (for additional details check the full version of the prehistory). In the first year of the Exodus three Frames entered new Corridors that led deep into Psychosphere. The Exodus began.