Among the previews of new den items was a book called Undead Slang, it is not in the den though. I only have access to 2012 onwards, so I checked in all three years and it isn't there. Is it possible that it has been put into an earlier wrong year accidentally?

Not in the 2011 section :(

Fixed!

(future reference, if an item seems to be missing out of a shop just ping me so I can fix it as soon as possible <3)

Okay, will keep in mind c: Thank you!

locking as resolved