The annual migration of clouds

The world is nothing like it once was: climate disasters have wracked the continent, causing food shortages, ending industry, and leaving little behind. Then came Cad, mysterious mind-altering fungi that invade the bodies of the now scattered citizenry. Reid, a young woman who carries this parasite, has been given a chance to get away -- to move to one of the last remnants of pre-disaster society -- but she can't bring herself to abandon her moth...