In a sunless world crawling with twisted creatures and a strange plague, a priest with no gods and a knight bound to a corrupt order must cross nightmarish wastes and crumbling ruins to protect the few people they have left. 

Sealed away behind the walls of Lumen, Cas struggles to keep the dwindling citizens alive without the gods’ magic once granted to priests such as himself. When he discovers an ancient entity and a mysterious text that convinces him there's a way to bring the sun back, he’ll risk leaving the comfort of those walls behind. ​Meanwhile, when one of Vice Commander Sol's ranks disappears, she sets out to find him. As she ventures forth, the glow of her lantern reveals not only the darkest corners of Lumen, but twisted truths and demons she must confront or be consumed by. 

As Cas and Sol’s paths converge at an unlikely crossroads, they must work together to bring light to their fetid world. Aware that they are humanity’s last chance for a bright future, they venture forth to fight the shadows that haunt them, lest they be reclaimed by the soil that made them.