One night, the archivist discovered a hidden channel in the file’s metadata—a string of coordinates that, when fed into a map, pointed not to a place but to a postbox in a town three hours away. In the postbox was a single, stamped envelope containing a small metal pull tab engraved with the CS tower logo and the words: “For mending.” The archivist thought it might be a marketing stunt—but the pull tab clicked into the zipper on Mira’s sleeve when she fitted it into her backup flash drive. It made the tiniest echoing sound, like a bell under water.