The Queen's Necklace — Teresa Edgerton

The ensorceled gems that once held all humans in sway now power a hundred small kingdoms, but the monarchy of Mountfalcon is suddenly in dire peril.  For the Queen has unwittingly lost the realm-sustaining, jeweled Chaos Machine -- a castastrophe that could tear the kingdom apart.  Captain of the Queen's Guard, Wilrowan Blackheart has been entrusted with the Machine's recovery -- an undertaking that slowly reveals a horrific conspiracy spreading far beyond Mountfalcon's borders, as the deposed Maglore plot to reduce the unsuspecting human world to rubble and flames. But unbeknownst to him, another has also embarked on the same mission:  a determined crusader of strength and substance...the only woman Blackheart has ever loved, but can never possess.