Teresa Amadei is a depressed young woman dealing with the sudden death of her mother, Juliana, with whom she has long been at odds since the murder of her father, Peter, when she was little. Her aunt and uncle, Bridget, and Jesse Abbate, send her to be helped by a Byzantine stylite in the Nevada desert, Father Simon. Father Simon trains her in the Way of Fire, a form of meditation that translates into a martial art, into a wandering, ascetic demon hunter and Lamp Bearer.

Teresa is sent on a journey to the city of Alexantine in the midwestern US, where many have started to move to as a refuge against the growing turmoil in the US and the West as a whole. Along the way Teresa fights the Daemoklos, demons who have escaped from their eponymous grimoire, led by their god-king Varazhah. Joining her on the road is her older cousin and fellow stylite, Matthew Abbate, and the Saracen, a mysterious knight with a mass following, whose identity and purpose remain unknown.

To survive against the outer demons, Teresa must face her inner demons. To defend the world, one must let go of and surpass the world, mentally and spiritually. Overcoming the enemy means overcoming herself: all of her thoughts, feelings, resentments, and regrets she has held her entire life. Key to achieving this, Teresa must at last make peace with Juliana, who continues to speak to her daughter beyond the grave.