This one starts in the past but it is Sci Fi.
Basically, in the early 1960s aliens showed up and announced that the Sun was going to be destroyed and you folks (the human species) were to be moved to safety. There were attempts at resistance, they weren't important because no one could do anything that seemed to affect the aliens or their machines and devices.
The population of the world where the PCs ancestors were taken, generally with their whole communities, including buildings and streets, intact, was drawn mainly from Europe, North America, North Africa, the West Indes, Indonesia, East Asia, and India. After a period of confusion, a stable democracy was formed. Limited contacts from other colony worlds were allowed for a few decades.
After the aliens deemed Humanity was settled, or as settled as they were going to be, they informed Humanity that were from a different universe. Humanity wasn't alone in this universe but the other races of this universe were very far away from both humanity and each other. The various human worlds were within reach of each other if people developed the right technologies.
That was the last the Aliens communicated to Humanity that the PCs know of.
Humanity had been divided into fifty groups and spread to as many different worlds. Each world seems to have been terraformed into something at least as good as Earth, if not in some ways better. The few tens of millions on each world grew their populations quickly, at least while the contact was maintained.
But that period was long ago in the late 1900s and early 2000s. It is now the year 2538. The people of the PCs world have achieved FTL drive. An exploratory fleet has been built to look for the other worlds of Humanity.
This is a TL12^ world with psionics. The style is
Raygun Gothic blended with just enough
New Wave to make things uneasy.