Xaviers!

It isn't precisely true to say the sun has gone out, though a few people say it might as well have. Even at noon, the light is sickly and barely enough to keep crops growing and keep the world from starving. The exact cause remains shrouded in as much darkness as the world, but whatever it was started in England and spread rapidly from there. An organization calling itself The Authority took over the British government, backed up by the power of magic and supernatural creatures. For some time, it looked like they would be contained to the British Isles and the rot would go no further, but then France fell and from there the rest of the continent. Rumors say that the United States tried to use Final Option to deal with the impending threat, but the bombs never went off. With both sides of the Atlantic covered in darkness, the rest of the world slowly capitulated rather than suffer for resisting.

There are still pockets of resistance calling themselves the Light & Life. The Authority rules everything with an iron fist, using werewolves, vampires and other supernatural creatures in addition to cooperative humans as its enforcers. Mutants are a wildcard in all of this. They're not given to one side or the other, but the Authority encourages people to report them and tries to scoop them up when it can. Something about what they can do for the Light & Life seems to scare the Authority and the Light & Life hopes to capitalize on that.