Pyro - The Elemental Underground, #1

Senior year is supposed to be special, but for Melissa Curran it starts off with spontaneous combustion and the unexpected friendship of two foreign students, Willow Caldridge and his twin sister Cierra. Melissa stresses about keeping her fiery secret from the newcomers, but then she learns the secret they've been keeping: they're elves from Parcia, a country that doesn't even appear on maps.  Melissa knows she will never return to an ordinary life, especially after a traitorous murder in Parcia reveals a bloodthirsty enemy.
Between the threat of a killer on the loose, Melissa's growing feelings for Willow, and her new tendency to accidentally set things on fire, senior year is shaping up to be the toughest year yet-understatement! Melissa has to face perilous danger in defense of herself and her new friends.