In a kingdom slowly choking on the dust of a dying world, hope is the most dangerous poison of all. The realm of Aeridor is trapped, languishing under a sky perpetually grey with fallout from the Ash World-a neighboring dimension collapsing from endless war. The Ash settles on the fields, sours the water, and seeps into the very lungs of the people, causing a creeping, incurable sickness known as the Dust-Lethargy. For Kaelen, a brilliant but desperate young scholar, the slow decay of his world is a tragedy he feels with every breath his ailing sister, Elara, takes. Driven by a love that defies law and a fear that eclipses reason, Kaelen turns from sanctioned knowledge to forbidden lore. He rejects the slow, certain death offered by the Ash and seeks a radical solution in the kingdom's other neighbor: the Shadow Realm. Shrouded in myth and religious terror, this dimension of deep night and silent, unknowable beings is said to trade not in cures, but in the essence of life itself. Convinced the answer to a disease of Ash must lie in its opposite, Kaelen risks everything. His search leads him deep beneath the hallowed Scriptorium, into sealed catacombs where the founders of his kingdom concealed their most dangerous secrets. There, he uncovers the Sunken Orrey, a breathtaking and terrifying piece of ancient technology with the power to gaze into other worlds. But in activating the device, Kaelen does more than just look. He attracts the attention of a sentient, ancient intelligence from the Shadow Realm-a being that offers a bargain for Elara's life. Now, caught between the approaching soldiers of the Ashguard and the soul-chilling whisper from the void, Kaelen must make a choice that will not only determine his sister's fate, but could also unravel the fabric of his reality and plunge the Kingdom of Ash and Shadow into a darkness far greater than the one it already knows.