All that Saphira has ever known is her world. She knows that nothing exist above the Surface. She knows humans died off centuries ago. For her, all that exist is the sea she calls home. But one night, one discovery, will leave her questioning all she's ever known. And one person will change her world, her dreams, her heart forever...

Kassie is a orphaned 16 year old girl that can turn into a cat and her species is frowned upon in her society so she has to go into hiding with her father figure, Ryan. After things start happening to her she begins to question everything that Ryan has told her, and this gets her in a lot of trouble.