Percy nodded. "Something like that. So, what, was it hidden under the floor or something?" He paused. "Or was it in the Mirror somehow?" Dumbledore nodded, twinkling, and opened his mouth to explain, but something was off, again, and Percy was barely listening as Dumbledore explained to a fascinated Ron and Neville how the Mirror would only produce the Stone for someone who wanted to get it but not actually use it. It sounded clever, hiding the Stone in the mirror, a perfect thing to tell people. Everyone would assume that they couldn't get the Stone simply because they were inadequate, but if you thought about it for a few moments... Percy was thinking of Bill and his tomb-raiding stories. The treasure's never in the chest - it's always somewhere else, and the chest is booby-trapped. There might've been a fake, perhaps, in case anyone managed to show really impressive levels of selflessness, but - "No," said Percy, drawing everyone's attention again, "it wasn't there at all, was it!"