In the kingdom of Kōsaten, the poor live by the mantra of "pair or perish." Outsider Macella should already be scraping to feed a family of her own, doing her part to keep the societal structure intact. Done with adhering to archaic expectations, Macella sets out on her own. Armed only with words and a thirst for change, she faces a perilous world, one where the veil between the mortal realm and that of gods and demons grows thinner every day.

In her pursuit of the stories she knows can incite a renaissance, Macella takes what work she can. But everything changes when, on her first night of brothel work, an Aegis-one of the kingdom's sworn protectors-requests her company. Aegises are known to be emotionless brutes, no better than the monsters they kill. But despite her fear, Macella is entranced by Aithan of Auburndale.

When Aithan begrudgingly allows her to travel with him, Macella convinces herself that their companionship is one of convenience, and that there is no deeper, more dangerous desire involved. But being around the Aegis is changing her. The voices in her head are no longer characters from her stories, but something far more real and infinitely more sinister. And she's not the only thing changing-monsters are entering the realm more freely, attacking more strategically. Something terrible is coming.

Yet Macella cannot walk away. Not when the world needs her-and Aithan does, too. Not when she finds herself wanting her story...to include him.