"I think.. this is information about the wards," Weasley said quietly, head tilting this way and that as he looked at the numbers that had made no sense to Draco. "This number here," he pointed to a string of six or seven numbers at the top of the page, "look like a key. A sequential system of wards, built on top of one another. Alarms, blocks, defenses, a whole web of them."