The Sigil. Adeline Crown Ghost Stories, #1

Adeline Crown can talk to ghosts. She's always been able to talk to ghosts, and was lucky enough to find her way into the small community of people like her. People who can also talk to ghosts, or breathe fire, or any number of abilities outside the human norm. When something split the sky in half and kids across the world started waking up with similar abilities, she and her colleagues decided they couldn't let a whole generation suffer in fear and confusion, and revealed themselves to the world.
The extranatural community has always been there, and now one out of every six kids is a part of it. Lindsay Fisher is one of those kids. Her teacher contacts Adeline in an attempt to figure out what's wrong with her and how he can help, handing her a thread that will unravel far closer to home than she expects.