Caleb West, an ordinary Chicago ER nurse's husband who unknowingly carries angelic blood and a hidden Nephilim fate, is attacked by a Demon Wolf and begins transforming into a supernatural guardian. Guided by Azrael and allied with hunters and supernatural teams, he fights Lucifer's agents as Chicago descends into escalating chaos. The core premise is a growing war between good and evil played out through escalating supernatural incursions targeting-and ultimately threatening-the stability of reality itself