In the seventh installment of the series, detective Mick Hargraves and his bound demonic partner Marchosias are forced to settle a long-standing debt when the powerful infernal Lilaeth calls in a favour. The task requires them to liberate an ancient, celestially imprisoned entity known as the “Muted Prophet” or the “Bound Voice,” which has been silenced for twelve millennia to prevent the “containment of consequence” associated with its ceaseless, oracular speech. The investigation begins in the quiet halls of the British Library and leads to the shadows of the Infernal Market in Paris, where the sources explain that freeing the entity requires reassembling a shattered Achaemenid bronze disc hidden across ancient sites.
The mission escalates into a perilous international trek through the Alborz Mountains, the underground sanctuaries of Isfahan, and the salt flats of the Dasht-e Kavir. As Mick recovers the fragments under the threat of modern military operations and lethal celestial-grade wards, he is pursued by rival factions, including the brutal Duke Vorath and the manipulative Dantalion, who seek the entity’s power for their own ends. Amidst the cosmic horror of Göbekli Tepe, Mick must rely on an obsidian binding stone from his own past to confront a pre-hierarchical guardian, all while questioning if he remains truly human after years of navigating the liminal spaces between life and death.