Stolen Magic by Linsey Hall

Being a FireSoul has its perks. Cass Clereaux can find any type of magical treasure—or steal any type of magical power. She’ll pick hunting treasure any day because she doesn’t have to kill for it, but that doesn’t mean she hasn’t stolen powers. She needs them to stay alive. Because a fight to the death is the least of what she can expect if other supernaturals find out what she is, she’s become an expert at laying low.

When her friend is sucked into a magical portal, she’s the only one with the power to help him. But what she uncovers is a danger greater than she’d ever imagined—and linked to her past in a way she’d never expect. Worse, the portal puts her whole town at risk. As the threat grows, she must confront her fear of losing control of her new powers, or lose any hope of saving hundreds of lives.