So my plot idea is rather unformed, but overall goes something like this. Based upon the multiple worlds theory governed by quantum physics, there are multiple worlds abundant throughout an influx of space and time. It's relatively difficult to traverse but it does exist. And our world, yeah we're better off if we didn't mess up other worlds on top of our own. One day though, our world is visited. In another world, one governed by a magical form of science and one where people aren't always fully human. their world is dying, and their powers no long work on it as their universe has grown too used to their magic to be effected by it. it's built of a natural immunity, and without their magic to help them with everything from growing crops to cleaning their water to everything else, their society doesn't know how to function or survive. Which is when they came up with the idea. They traversed the multi-verse and came up with the short end of the straw and settled here. Coming to this world they introduce themselves with this story and set up shop, agreeing not to get into this world's countries squabbles or take any one side against the other in the human's wars. The humans are skeptical at first but eventually grow to accept the other group. There are obviously many ways I could take this story like perhaps generations later the same thing that happened to their world is happening to ours and they know this and they do this jumping from world to world.