The book is set in a fantasy-world equivalent of Byzantium. The title refers to going to Sarantium in order to find opportunity or the cost of failure in not standing up to that opportunity.
The protagonist is a mosaicist who goes to Sarantium in place of his master to build a mosaic for the King. There is some courtly intrigue and it has interesting and well-developed characters.
I’m not sure why it’s set in a fantasy setting, as the fantastic elements seems of negligible importance and could have been achieved by other means. It could easily have been set in Rome or Byzantium, among other ancient cultures.
The book got off to a slow start, but became much more interesting when the protagonist reached Sarantium.