After nuclear fire choked the skies and turned the sun to ash, humanity survived in the shadows; beneath artificial light and the unrelenting control of Helion, the corporation that rationed every breath, every lumen, every heartbeat. The world below was silent, its hum the only rhythm left.

But when a fissure tears open in the dark, revealing the Radiant Core; an ancient, living source of light buried deep in the planet; Jonas Vale becomes the unwilling conduit between humanity and a power far greater than Helion ever controlled. Linked to the Core by fragments in his blood, Jonas is the only one who can modulate its radiance, balancing a force that could burn the planet to cinders or remake it into something unrecognizable.

With Kael, a relentless strategist; Biran, a scarred engineer; and Lira, a marksman hardened by years in the dark, Jonas must hold the Core's spectrum steady as the old world unravels. Helion's order collapses, ecosystems mutate under the new sun, and humanity faces a choice: adapt to a planet reshaped by something not of Earth; or vanish with the shadows.

As the Core's pull threatens to consume him, Jonas must decide whether to surrender to a power that sees him as nothing more than a thread in its web; or sever the bond and risk plunging the world back into darkness.