Day Watch (Watch, Book 2) Sergey Lukjanenko

The morally ambiguous second volume in Lukyanenko's trilogy (after 2006's Night Watch, a major literary and cinematic success in Russia) portrays the epic supernatural struggle between good and evil from the point-of-view of the witch Alisa Donnikova. Lukyanenko imagines a parallel reality, where human history has been shaped by a centuries-old conflict between the Dark Ones and the Light Ones, magical beings whose existence is kept carefully hidden from humanity. After Alisa, a Dark One, loses her powers in a minor confrontation with some Light Ones, she heads to the Crimea to recuperate at a girls' camp, where she feeds on children's nightmares. There she falls in love with Igor, who turns out to be a Light magician.