She remembered well enough listening to the twins talking about the passages of Hogwarts. Perhaps they didn't realize that she was listening; after all, Hermione Granger was the well-to-do bookworm Prefect. She wasn't exactly known for rule-breaking. They had been speaking to Harry, of course, when they mentioned a passage behind a mirror that had caved in during Harry's second year. She disregarded it, but then later Sirius mentioned it again, saying that it was large enough to hold DA meetings in. It would be many years before it would become unusable, so Hermione fully planned on taking advantage of it.