This is a standalone novel; like most of Tarr's work, it takes a historical story and weaves fantasy elements into it.
This is the story of the mother of Alexander the Great, and an interesting vision of religious magic in those times. Tarr does a good job with magic, as usual, but her characters are less real and engaging than in many of her books. There is an interesting underlying story of the power of women in the world, told through a rather different version of ancient Greek religion than what we learn about when we study mythology in school. I'm curious whether she made it up out of whole cloth or if there is some historical basis for the idea that people of that time identified Hera, Artemis, and Aphrodite as aspects of a single primal mother goddess.
The history and the magic together make a great background, but the foreground story is only moderately good; overall, certainly readable but far from great. 7 out of 10.
**** PLOT SUMMARY -- SPOILERS ****
Polyxena is a priestess in training, but she doesn't feel called to it. There were very bad omens around her birth, and her mother Nikandra has tried to avert them by not training her in the use of her magical powers. Trying to avoid fate is always a bad idea in ancient Greece. Polyxena uses her untrained magic to try to reach out to the oracle and causes an earthquake. She is then sent to Samothrace for the Mysteries there. There she demands to be initiated in the deeper mysteries, not just the stuff the ordinary pilgrims see. She takes the role of the goddess in a great rite, and meets Philip, who is taking the role of the god. They fall in love. He goes home to Macedon, but he sends an embassy asking for her as a wife. Her father is reluctant to allow her to be one of many wives, but she wants to go. Philip gives her a slave, Erynna, and a new name, Myrtale. Erynna is a witch from Thessaly, who appears to be her ally and teaches her some magic, but when Erynna tries to murder the child of one of Philip's other wives, Myrtale realizes that she is an enemy, and understands that they mean to control her child. She refuses to allow them that control, and goes through a major magical ordeal, where most of the magic is mental, magically induced despair, rather than lightning bolts and such, and in the end wins out, destroys the witches, and wins for Alexander the freedom to choose his own destiny rather than be controlled by those who would rule through him.