I am on p 114 of "The Deathly Hallows" and notice a very important message
Spoiler alert for the 3 other people who haven't finished the book.
"It Opens at the close" I guess this refers to a heavy locket mentioned in "The Order of the Phoenix" which no one could open.
update: now page 158. A while ago, I predicted
When cleaning 12 Grimauld Place a heavy locket which no one could open was found.
In book 6 (half blood prince) we encounter the concept of Horcruxes. One bit is in his reconstructed body, another was in the Riddle diary (killed in book 2), another was in a ring destroyed by Dumbledore.
One is clearly in a locket once belonging to Slytherin.
This was replaced in its former hiding place by an ex follower of Voldemort who signed R.A.B. . One Regulus Black (brother of Sirius) was once a follower of Voldemort. He was quickly killed after he tried to switch sides. I assume he is RAB and that the locket is the one found in 12 Grimauld place. I guess that there will be an effort to find where Kreacher hid it, then it will be discovered that Fletcher sold it. This should be good for hundreds of pages.
All correct so far (only have Kreacher's word on Fletcher) except for the bit about "hundreds of pages".
Update: well my old predictions are basically all correct. I blew it and made an incorrect prediction about the meaning of "it opens at the close" which has nothing to do with the locket.