Morrigan's cross - Nora Roberts

Modern-day New York: Glenna Ward is a strong, independent woman. She is also a witch, and knows that one day her powers will be put to the test. When the mysterious Hoyt Mac Cionaoith enters her life in the strangest of circumstances, Glenna finds herself irresistibly drawn to him. But even she is unprepared for the reason he has sought her out and the danger that lies ahead of them.

Twelfth-century Ireland: Hoyt Mac Cionaoith is visited by the goddess Morrigan and charged with the ultimate task: to save his and all future worlds. Hoyt's enemy is Lilith, the beatiful but deadly vampire queen who recruited Hoyt's twin brother, Cian. Five others must join Hoyt in his battle to defeat Lilith: 'the witch, the warrior, the scholar, the one of many forms, and the one you've lost'. Now he must find them, before it's too late. And Glenna is the first on his list . . .