Aza Ray Boyle has always been unique, defined by a mysterious lung disease that makes it increasingly difficult for her to breathe, speak, and live. Her life takes a turn when she glimpses a ship in the sky. While her family dismisses it as a medication-induced hallucination, Aza knows it's real. She can hear someone calling her name from the ship.

Her best friend, Jason, is the only one who believes her. Jason has always been there for Aza, and she harbors feelings for him that might be more than just friendly. But before she can explore these feelings, something goes terribly wrong.

Aza is lost to our world and found by another—Magonia. Above the clouds, in a land of trading ships, Aza discovers she is not the weak and dying girl she once was. In Magonia, she can breathe freely for the first time, and she possesses immense power.

As Aza navigates her new life in Magonia, she learns of an impending war between Magonia and Earth. The fate of humanity, including the boy who loves her, lies in her hands. Aza must decide where her loyalties truly lie.