Once upon a time, there was an eighth son of an eighth son who was, of course, a wizard. As if that wasn’t complicated enough, said wizard then had seven sons. And then he had an eighth son—a wizard squared (that’s all the math, really)—who, of course, was a source of magic, a sourcerer. Unseen University has finally got its wish: the emergence of a wizard more powerful than they’ve ever seen. As the drastic consequences of sourcery begin to unfold, it’s up to one unlikely wizard to save them. Rincewind has survived a string of misadventures, including falling off the edge of the world—which is no mean feat when it’s flying through space on the back of a turtle and held up by four elephants. Now, he must take the University’s most precious artifact and deliver it halfway across the Disc to prevent a mathematically blessed sourcerer from leading the wizards to dominate all of Discworld.