Lords of the Seventh Swarm by David Farland

“This is incredible. My mantle has no information on these masks; as a Lord of Technology, I should know something of them.”
    Gallen’s own mantle whispered to him. “The nature of the artifacts discovered here has been classified as secret. It is vital that such technology not fall into dronon hands.”
    Until now, Gallen had thought it exceedingly odd that the government would conspire to hide an entire world. Now he got an uneasy feeling that they had stumbled onto something darker and more important than he ever would have imagined.
    Softly, Maggie asked, “What proof do you have of such a level of technology?”
    “Ah,” Felph smiled. “I see your reservations. A technologist doesn’t want dreams and alien voices whispering in her ear. She wants hardware.” He bent his head. “Unfortunately, not much has survived the past twenty thousand years. You can search the aeries—the Qualeewoohs call them cloo holes, but all you will find are cave paintings. But some evidence exists. Come back here, into this passage.”
    Felph hobbled to a hole that had been excavated in the back of the chamber, then led them through a corridor that sloped down, then suddenly opened into a far larger chamber, an almost perfect oval.
    Here, things were far different from the room above. Felph had installed a very dim continual light on one wall. Mounted on the wall opposite from the light was bolted a metal panel with graceful lines etched deeply into it. Whereas the previous walls had all been covered with exotic pictographs, these loops and whorls were clearly different. They didn’t seem to be writing. They didn’t represent anything.
    “Can you guess what this is?” Felph asked.
    Maggie drew close and studied the metal panel. “This isn’t the low-quality silver we’ve seen on Qualeewooh spirit masks. This is a solid sheet of platinum.” The panel was nearly two meters tall and ten long. “Something this big had to have been milled in a foundry.” She studied the grooves in the metal. They followed two separate tracks, mirror images of one another, that led from the floor to the ceiling and back down again in graceful sweeps. “It looks like writing etched into the metal,” Maggie said, uncertain.
    But even Gallen guessed that these weren’t pictographs, not representational characters at all. “These etched tracks are so narrow and deep: the grooves must have been cut with a laser.” When she examined the etchings closely, she suddenly bolted backward in surprise.
    “A recording?” Maggie said, astonished. “These grooves are an audio recording?”
    “More than just audio!” Felph said. “It’s an audiovisual recording from the second expansion, approximately thirty thousand years ago. This predates nearly every civilization on Earth. Our ancestors were just learning to shape stone, while these people were developing laser technology and recording studios, performing brain surgeries and actively terraforming their own planet to make it more suitable. You should see the stone aqueducts on Fire River—over four thousand miles of covered aqueducts in all—and most of it is still usable.”
    Felph brought a small device from the pocket of his robe, something that looked like a high-tech top—a spindle on a round spool with a thin, curved handle. He placed it in one of the grooves on the lower right-hand corner of the metal plate, and twisted. There was a snapping sound as a lock snicked open. A heavy rumbling followed.
    A hole opened in the stone floor, and a statue began rising up, revealing the shape of a birdlike creature sculpted from colored glass. The figure was corroding, miserable in appearance, but Gallen could sense the general appearance of the being.
    The Qualeewooh had light-colored feathers on its chest, while the longer plumage on its wings was mostly tan with some green tips at its wings. The statue showed the creature with its wings upraised, and Gallen could distinctly see the tiny