They sent a rover first. It rolled, cameras on, into the seam. Its wheels scraped crystalline sand that shimmered like ground glass. The video feed blurred as if someone had breathed across the lens. Then the rover’s main camera flattened into a single, clear image: a chamber lined with carved glyphs in repeating patterns reminiscent of the sketches the crew had made. A single glyph, when magnified, resolved into the very phrase that had haunted them: Isaidub.