Colleen Garman is on the island of Capria, running for her life. The cult of Katharis is hunting her, men on the ground guided by a hijacked airship in the sky above.
As she gathers islanders loyal to Ben, prince of Capria, and prepares for a counterstrike, Colleen receives devastating news. Ben, the man who has come to mean everything to her, has been captured. He's being held in a castle in Sardinia.
A rescue attempt would be suicidal. Good people would die, and achieve nothing. It breaks her heart, but Colleen realizes that she has to let him go.
Ben's followers, though, are fanatical in their loyalty. With or without her, they will storm the castle to save Ben or die trying. Colleen has no choice but to join them on a mad balloon ride across the Mediterranean and a midnight assault on a fortress. The rescuers will pay a terrible price, but the cult of Katharis is going to take a beating it will never forget, and one way or another, Ben will be free.