In a world reshaped by the appearance of powerful entities known as "roots" that, for the past two centuries, have offered select humans immense supernatural abilities in exchange for binding contracts. These contracted humans, called diabolists, wield powers beyond ordinary comprehension but at a cost known only to the roots. Peter, a tenacious diabolist bound to his enigmatic root, Eva, joins forces with his longtime friend Jane to roam a perilous world. Together, they are commissioned to hunt and eradicate wraiths, malevolent spirits threatening humanity. Each encounter brings new mysteries as they encounter other diabolists, uncover hidden histories of the roots, and confront dangers both otherworldly and all too human. Unbeknownst to them, a shadowy conspiracy unravels in the backdrop, entwining their fates and pulling them toward a destiny none of them are prepared for—a dark revelation that will alter their understanding of the roots, the nature of diabolism, and the true price of their power.