Nocturnal (The Noctalis Chronicles, Book One)

Seventeen-year-old Ava-Claire Sullivan's mother is dying. Perhaps it's no surprise, then, that her greatest solace comes from someone who's already dead. Peter Hart saves her one night in a graveyard from an attacker just as strange as he is, and now Ava can't stop thinking about him. She wants to see him again - even after he warns her he's dangerous, and she begins to realize what he is. Her best friends don't know anything about death, but Peter does, intimately. He's waiting for her the next night she comes to the cemetery, and the next... But their growing bond comes up against a promise Peter made a long time ago, a promise that could destroy them both. Now Ava has to decide just what she's willing to give up to hold onto the one thing that could last forever.