The Burning Sky by Sherry Thomas -- 449 pages
Iolanthe Seabourne was only trying to cure a light elixir. She had no clue that by bringing down a bolt of lighting, she would mark herself as the greatest elemental mage of her time and set Atlantis on her trail. It's too late now, but at least she has an ally, a friend, someone prepared to help her....at least, that's what she thought. Prince Titus has his own motives for keeping her safe.
This is book 1 of the Elemental Trilogy. I had to go back to listen to the first two books again so that I could read the third, but I didn't mind. It's an exciting story.