The world of Arcadia exists in parallel and balance with ours. It is a world of magic and chaos, a counterweight to Stark, the world of science and order. The Balance between the twin worlds is watched over by the Guardian, who channels the energies of Chaos and Order between Arcadia and Stark.
Some people are able to move freely between worlds. These special individuals are called Shifters. There are not many left, and those who can Shift hide their powers well.
Some people can travel in a different way, dreaming themselves into other worlds, existing in two places at once. They are called Dreamers.