I loved Daughter of Hope and Reunion, the first two books in the Siaris Quartet, and I wasn't disappointed with Vow's Answer which I found just as engaging. The tension builds as Xereth and the Moraeth escalate their attempts to get what they want. They may not be driven by the same motivations but the end they aim at is the same. The writer has not made the mistake of making them entirely evil though. While our sympathies are with the Guardians and their seemingly endless battle to preserve the world and people they are bound to protect there are flashes of what makes the Morraeth what they are and explains why they behave as they do while Xereth's obsession with the past fuels his rage making both the fallen Guardian and his masters believable.
I recommend Vow's Answer highly and I'm waiting impatiently for the final novel in this engrossing series.
Vow's Answer was published in December 2013 by Urania, the speculative fiction imprint of Musa Publishing, and is available as an e-book from Amazon.com and the publisher.
Joanna Fay's website is here and she is also on Facebook.