Thin Air by Rachel Caine
On top of that, it was raining. Joanne Baldwin has had better days - at least she hopes she has. After waking up naked and freezing in a forest, she's located by two rescuers she doesn't recognise at all. One supernaturally gorgeous guy might have been her lover. The other says he can control the weather - and so can she. Not everyone looking for Joanne has her best interests at heart, and with no way to tell friend from foe, Joanne is quickly lost in a fog of deception. Her tenuous hold on life is fading with every passing moment. Now she must rebuild herself, one memory at a time, before someone else steals her life - and she disappears into thin air. Oh, and along the way, it seems that she has to save the world.