The Gathering Storm — H.K. Varian

When four middle schoolers discover that they can transform into mythological animals, they become part of a powerful, hidden world -- the world of Changers -- in this wild new urban fantasy series.

Mack, Fiona, Darren, and Gabriella aren't exactly friends at their middle school -- in fact, they couldn't have anything less in common. But when they start developing powers, including the ability to transform into mythological animals, they find out that they are Changers, a magical line of shapeshifters that history has forgotten. But there's little time for questions. A powerful warlock is racing toward their town, destroying everything in his wake. Can Mack, Fiona, Darren, and Gabriella harness their newfound powers in time to save their home? Can they even stop arguing before the last bell?