Maya had one card left to play. She remembered Carl’s muttered words: unsalvageable legacy code . The Meridian’s original building management system ran on a separate, air-gapped network—a relic from the 1990s that controlled only the oldest systems. The dumb ones. The manual overrides for the fire doors, the backup water pumps, the emergency lighting. They weren’t connected to the internet. And they weren’t on the worm’s schematic.