I was impressed with this book.
The premise of this book is that a strange phenomenon happens, called the Exchange, where part of our world is switched out for part of another world, an alternate world. No one knows why, or even how it happens. But scientists are able to somewhat tell when it is going to happen. But the people in the ''Exchange Zone" (or EZ) only have a few hours to get out before they are teleported into the alternate reality, and in the place where they were a chunk of the other reality replaces them.
It was a delightful, quick read. For young adults to adults. 14+ I would say.
I love it lots and totally recommend it.