A book to give you a taste of what Half-Blood will be like. Alex comes out as a strong independant girl and very much reminds me of Dru from Strange Angels series by Lili St.Crow whom I adore.
The prequel describes Alex and her mom on the run and hiding from Covenant. There is no explanation why they run, but Alex's attempts to live a normal life and go to school are pretty amusing, until her family is found by daimons. Then her only thought is to get back to Covenant.