This Pratchett novel is different from most of his Discworld books. Except for the first few chapters, most of it takes place outside Ankh-Morkpork. In the opening, the main character, Teppic, is studying in the Assassins Guild. To survive in the Guild long enough to make it to graduate day is to qualify for the graduation test. To graduate the candidate must survive the test which lasts all night long on the streets of the city.
Alas, soon after graduating, Teppic is told his father had died and he must retire as an assassin because he is now the king of an Egypt-like country Djelibeybi. Once Teppic gets back, he finds he is only a figurehead; the ancient (really, really ancient) high priest runs the country.
As with all Pratchett's novels, this one is filed with bizarre events and characters. Djelibeybi is stuffed with pyramid tombs for the previous kings. Teppic determines to build the largest one yet for his dead father who is annoyed because he doesn't want a big tomb but no one listens to him because he's dead. The tomb is so huge, it distorts space-time and forces it to rotate it by one dimension.
Another major character is an old camel named You Bastard who is the world's greatest mathematician and a dead-eye spitter.
This story is better than Pratchett's average discworld novel.