Vault of Embers

A dormant supervolcano hides something that shouldn't exist—a geometrically perfect metallic structure older than civilization itself. Volcanologist Dr. Eric Colfax expected to find magma chambers and fault lines beneath an Indonesian caldera, not star maps etched seventy-four thousand years ago. When identical structures awaken inside four supervolcanoes simultaneously, Eric joins a desperate team racing to prevent a synchronized eruption that could end the human species. But the deeper they descend, the more they realize the greatest threat isn't the volcano—it's the ancient intelligence deciding whether humanity deserves to survive.