Mara crouched at the junction and spread her old charts against the damp wall. The ink past this point was blank, wiped clean by tunnels that wouldn't sit still. Her air gauge ticked. She had come to finish the atlas, to save the last route before Retchmaw swallowed it, but without a bearing she would wander until her lungs gave out. A flicker of color caught her lamp. A ribbon-bodied creature clung to the seam where two passages breathed, its quill antennae twitching toward a current she couldn't feel. It hopped, paused, hopped again, always into the same throat of tunnel. Mara watched, then pressed her palm to the wall and felt the faint pull it followed. She marked the bearing in fresh ink. The blank page had a first line now, and she stepped after the creature into the moving dark.