After spending five years on a hellish island in the vicinity of China, billionaire playboy Oliver Queen returns home to Starling City, but finds things much different from how things were left. Using the skills he developed on the island, it is now his duty to clean up his city. But there are others at work, others who are just as formidable as him, all with their own goals, and of course his family and friends, who have to adjust to his return.
Meanwhile, things haven't been quiet elsewhere. Just prior to Oliver Queen's return, S.T.A.R. Labs began experimenting with a particle accelerator in Central City. The result of the activation caused a tear in the dimension, causing all sorts of unknown energy to leak in. Metahumans have been born as a result, those who fight for justice, and those who serve their own ends.
But that's not all. The world is filled with other beings who didn't need the accelerator to become powerful. Mysterious beings and entities have already existed, and in this new time, they are making themselves known.
We base ourselves on "Arrow" and "The Flash", but by no means are bound to them. Feel free to make your own versions of characters who have already appeared in the show, and thrive in this universe.