Shift is the prequel to The Wool Omnibus. It primarily tells the story of how the underground silos came to exist and why the world became unliveable. The first half of the book is very different from Wool, and much slower. It starts with Donald Keene, a congressman involved in a top secret project to build an underground facility. He believes the lie he’s fed about the facility’s construction, and is quickly trapped into an existence he had tried to believe wasn’t possible.