Heaven and Hell are warring on Earth, and Ander Castillo is stuck in the middle. Ever since demons broke through the gates of Hell and decimated humanity, Ander, along with other "blends"-humans with angelic blood-has been hiding in Gardners, one of the few remaining sanctuaries. The decrepit city is watched over by strange, distant angels, who protect its residents but offer no advice or comfort.

Leaving Gardners is a death sentence, but love drives Ander to attempt the impossible and set out beyond the walls to find the foster brother he lost long ago. Yet Ander's no true angel, and a few feathers on his neck can't save him from the monsters running wild over Earth. Soon enough he faces an impossible choice: a vicious death or making a deal that will tie him to a bloodthirsty demon. Forever.

Everything is not as it seems, though. Ander's left wondering if evil can wear an angel's face or love can hide in a demon's luminous eyes. As he and his new deal-bound "partner" are drawn into the affairs of entities far beyond them, Ander's strength and resolve are tested, and only love and loyalty will give him a chance at a future worth living.