Book Two in the Wolf Breeds series.

They are a new breed, a new race. Engineered rather than born, trained rather than raised, and their unique genetics have created more than one surprise.
 
Jacob left Faith six years before, unaware that the mark he left on her also left her in an agony of sexual heat that never dimmed. Now Jacob and Faith are together again, but surprises lurk around every corner and dangers as dark and deadly as their very creation surround them in more ways than one.