Unearthly (Unearthly, #1) by Cynthia Hand

In the beginning, there's a boy standing in the trees.

Clara Gardner has recently learned that she's part angel. Having angel blood run through her veins not only makes her smarter, stronger, and faster than humans (a word, she realizes, that no longer applies to her), but it means she has a purpose, something she was put on this earth to do. Figuring out what that is, though, isn't easy.

Her visions of a raging forest fire and an alluring stranger lead her to a new school in a new town. When she meets Christian, who turns out to be the boy of her dreams (literally), everything seems to fall into place—and out of place at the same time. Because there's another guy, Tucker, who appeals to Clara's less angelic side.

As Clara tries to find her way in a world she no longer understands, she encounters unseen dangers and choices she never thought she'd have to make—between honesty and deceit, love and duty, good and evil. When the fire from her vision finally ignites, will Clara be ready to face her destiny?

Unearthly is a moving tale of love and fate, and the struggle between following the rules and following your heart.