Gelya is a Vessel, a girl who channels the word of the One True God through song. Cloistered with the other Vessels of her faith, she believes—as all Ovinists do—that a saint imprisoned Elath the Great Demon centuries ago, saving humanity from earthly temptation. When Gelya stumbles into a deadly cover-up by the Ovinists’ military, she reluctantly teams up with Tavik, an enemy soldier, to survive. Tavik believes that Elath is actually a mother goddess who must be set free, but while he succeeds in opening Her prison, he inadvertently turns Gelya into Elath’s unwilling human vessel. Now the church that raised Gelya considers her a threat. In a race against the clock, she and Tavik must find a way to exorcise Elath’s presence from her body. But will this release stop the countdown to the end of the world, or will it be the cause of the earth’s destruction? And as Tavik and Gelya grow closer, another question lingers between them: What will become of Gelya?