Orphan's Fate (Sci-fi/Fantasy story)

Sophia and Aidan were survivors from the violent floods that swamped the world just under a year ago. Thinking they were nothing but ordinary children, they're surprised to find themselves mentioned in an alien prophecy. Soon they find themselves teaming up with Kyllgar, a Zaghgale, to help banish the Nadverians from Earth, and thus rid the world of global warming. They meet many more friends and enemies in their long journey, and learn of their hidden talents that will help them during their quest to fulfill the prophecy.