A group of tourists travel together on the "Canterbury Trails" bus to visit "The Impossibles". Those are seven of the most impressive "reality glitches" located in the USA that appear after it's discovered we live in a simulation. There's a little about simulation theory and a lot of time on the characterization of each of the travelers. There's not enough space here to do this book justice. It's as good as anything I've read by Gregory. A little less mind-bending than some of his stuff and deeper characterization. I liked the ensemble cast -- would make for a truly good TV series.