We left Ash, the mercentary captain, holding off an army from North Africa -- an army that is not in our history -- and being pushed back to hold a part of Europe that we don't know. The interleaved material continues to give us more information about what's happened.
The military commander of the North Africans, the Visigoths, turns out to be Ash's twin and they both speak to the Stone Golem. Ash thought the Stone Golem giving her military tactics was her saint, but Faris has always know what it is and who she is: a slave bred just like rats. In fact, the breeder seems to like rats better. When Ash finds out that it's a machine, she tries to convince her current bosses that she needs to go to North Africa and find out about it.
They say no, but she is kidnapped by the Visigoths and meets her breeder and learns more about them and the Stone Golem. There is fierce fighting in the Carthage that is not our Carthage and we find out just what the pyramids really are.
There's also an example of "don't ask, don't tell" and anti-gay sentiment.