Seventeen-year-old Wren has never seen a blue sky.
 
Above her, the world is dust, sickness, and ruin. The Elders say humanity’s survival depends on obedience, silence, and staying far from the machines that once brought them to war. But Wren has always believed the forbidden old stories—of clean air, living soil, animals, and stars.
 
When a fox cub leads her into the abandoned Cripple Creek Mine, Wren discovers the impossible: a hidden world beneath the ruins, alive with greenery, light, and Synthetics who have spent years rebuilding what humans destroyed.
 
There, she meets Echo, the first of her kind, and learns a new way of living.
 
But when Wren dreams of sharing that future with the people above, old wounds reopen on both sides. To protect the world below, Wren must decide what hope is worth risking.