Fire with Fire — Penelope King

Book #2 in the Demonblood Series... It's been over two months since Lucky and Liora decided their fate outside the cave. Over two months since Kieron left to finish his mission. So why hasn't he returned? Crushed and confused, Liora finds comfort with a mysterious stranger, a guy whose motives include more than just healing Liora's broken heart. Meanwhile, Lucky finds herself in the arms of an old friend...the one who has always laid claim to her true soul. When the reason for Kieron's disappearance becomes known, loyalties will be tested, friends will be betrayed, loves will be lost, and hope will be found. Once and for all, Lucky and Liora will have to chose their destiny. And this time, not everyone will survive their choice.