The Vanishing Throne (The Falconer Trilogy, Book #2) by Elizabeth May
When we last saw her, Aileana Kameron, the Falconer, disappeared through the fae portal that she was trying to close forever. When she escapes and reenters the human world, she finds her beloved city—indeed, the entire world—has been destroyed, and the fae world itself is slowly dying. Somehow Aileana is the key to preserving both worlds—but how? This much-anticipated second chapter in the Falconer trilogy "combines vivid world-building with action-packed fight sequences" (School Library Journal) "and a cliffhanger ending ensures that readers will follow Aileana to the very end of this trilogy" (The Bulletin of the Center for Children's Books).