This is Book Two in the Tris Grima series.
With the help of her sexy gargoyle, Hugh, Tris Grima continues to search for those responsible for her mother's death. What she discovers instead is that her grandmother was once part of a powerful coven. Only one coven member has survived to guard their grimoire ... and now it has been stolen.
Warning: This addition to the series has witches, crazed frost sprites, a mysterious Dark Lord, and a nine-foot-tall white werewolf nicknamed Frosty.