The prison-city of Osylum floats in the midst of an endless abyss. The reclusive Lady rules it; distant, inscrutable, and never seen. Her will is imposed by the Wardens, eldritch creatures who tend to the convicts' needs but also ruthlessly purge anyone who tries to escape. Osylum's newest inmate, the witch Oneirotheria, has no memory of who she is, where she came from, or why she is imprisoned. Instead, her mind is a mess of spells...