Literally what the title says.
Here's what I am thinking, every single member of the Bat-Clan has recieved their own silver platter and tray. (I have deduced this from Teen Titans issue 16)
That means that Alfred isn't necessarily dead, but every member is recieving something that is significant and heart wrenching. Alfred could be presented as one of the items, along with someone from Nightwing's past or current relations (thumbs crossed it isn't Sonia Zucco, Raya even though she's dead, or the little girl Christina), Barbara Gordon's mother, Titus or one of Damian's pets, Tim Drake's parents, or Jason's Mom.
Another thing I have noticed is that Joker is bringing each of the members to a secluded area that looks like a familiar cave scene.
And finally, Joker has said that Batman will kill the members of the Bat-family, and I think that he means this in a literal sense.
There has been speculation that the meaning of the arc is for a figurative sense, and though I feel like that will be the final outcome, Joker's drive is for the Family to be destroyed one way or another, and knowing that most of the family is alive for future stories, Joker won't succeed literally, but he might succeed in breaking down the overall dynamic of the Family. I also have a feeling that the cave and Manor will be taken down as well, just a hunch from a glimpse of art.
But the big question is whether or not Joker will die, and from this little preview, he could.
All ideas, and predictions are welcome in a sane and respectful manner.