Zetsuen no Tempest
Hakaze, princess of the Kusaribe mage clan, has been betrayed and marooned on an island by her own people. They seek to revive the Tree of Exodus, an incomprehensibly powerful entity of alien origin, to save the world from the tyranny of its antithesis: the Tree of Genesis that powers their magic. Hakaze, however, believes their efforts put humanity in jeopardy; and with her power limited, she can only reach out to the world to beg for aid. Her call reaches Mahiro Fuwa, a young man grieving the mysterious death of his sister, Aika. He and his friend Yoshino agree to help - on the condition that Hakaze track down Aika's killer with her magic. The deal is made, and the battle that will determine civilization's fate is begun: but who will play the part of its villain, and who its savior?