Mistress of Hours by Emma Elizabeth

Evienne is living her dream as the highest-ranking blood mage in Ichorna when the queens assign her to monitor two unexpected visitors from their elusive northern neighbor of shifters, Beitar. She can’t help her curiosity when one of the visitors–a striking academic with piercing green eyes–seems determined to seduce her. What starts as a dalliance pulls Evienne into a web of centuries-old secrets that could turn her world, and her understanding of her power, upside down.

Orion, a professor from Beitar, arrives in Ichorna to attend their turn-of-the-millenium celebration with a singular goal in mind– he must find answers about his people’s dwindling magic. He needs an Ichornian ally, though, and the alluring blood mage Evienne may be the key to his success. All his plans are upended, though, when an ancient magic awakes in his soul.

Despite their different allegiances, Evienne and Orion decide to work together to uncover the truth of Beitar’s failing magic. As the horrible threads of the past unravel in the present, Evienne must choose between loyalty and her own integrity. The lives of a whole nation hang in the balance.