She explained all that went down with the Salazar Slytherin’s locket – how Harry and Dumbledore went to retrieve it on that fateful night and how the Horcrux wasn’t where they thought it was, so all that effort was for nothing. She told him how they found the real locket half a year later but couldn’t destroy it because they didn’t know how. Eventually, they destroyed the locket during the Battle of Hogwarts using Basilisk’s poison from the fangs because that’s how Harry had destroyed the diary.