The Ash Cities

A century after the Cataclysmic Eruption plunged the world into perpetual twilight, humanity clings to survival in Subterra, a claustrophobic network of underground cities.  The sun is a forgotten myth, the surface a toxic wasteland. But for Kieran Holt, a young cartographer haunted by whispers of the past, the surface holds a desperate hope: the legend of a hidden civilization that thrived amidst the ash.
Driven by faded maps and an unwavering belief, Kieran embarks on a perilous journey to the surface, joined by the pragmatic engineer Teresa Gonzales.  Their ascent is a harrowing odyssey through crumbling tunnels and poisonous air, a stark reminder of the world lost.  Emerging into the ash-choked landscape, they discover Xylos, a breathtaking city woven into the volcanic rock, its air miraculously clean, its people vibrant and resilient.  Xylos isn't just surviving; it's flourishing, thanks to a lost technology that cleanses the toxic sky.
But Kieran's discovery ignites a firestorm of conflict in the subterranean world.  The promise of the surface fractures the fragile peace between the cities, sparking a desperate power struggle for control of Xylos and its transformative technology.  Metropolis, a technologically advanced city, sees the surface as a resource to be exploited, while Aetherium, a spiritual community, believes it is sacred ground.
Caught in this escalating tension, Kieran, Teresa, and Xylos's enigmatic leader, Samantha Baxter, forge an unlikely alliance.  They must navigate a treacherous political landscape while uncovering a darker truth about Xylos's origins — a secret that could shatter humanity’s last hope or pave the way for a new dawn. As the underground cities clash in a brutal three-way war for the surface, Kieran must grapple with a terrifying dilemma: is Xylos a gift of salvation, or a Pandora's Box that will unleash a new era of destruction? The fate of humanity rests on his shoulders, his choices echoing in the ash-filled sky, where the faintest glimmer of sunlight promises a new beginning… or a final, devastating end.