Soul Mates is book 3 in the Dark Earth series
Stephanie is a witch. Not the catty steal-your-boyfriend kind of witch either. She can feel a person's hopes and fears and burn the blood in their veins. Or at least that's what her Mistress says she should be able to do. Mostly she summons breezes to blow piles of leaves around.
And that's a problem. With her ruler planning a war to take over her old home, The United States of America, she's got to come up with a way to stop him and save herself and her Mistress in the process. It's a tall order for a high school dropout that's screwed up every choice she's ever made.
Look for these other Dark Earth books:
Dark Earth
Devil's Icebox
Soul Mates
Voices
Bound
also The Lost Girls series