I'm Looking for this book - can anyone help?

Hey guys. I can vaguely remember a book I read a while ago and want to find again, but I can't remember the title/author. I found a different book this way so thought I'd give it a shot. This is all the details I remember about this book - does anyone know it??

It centres on two girls. They used to be pretty close but kinda began to drift apart and Girl A finds this new group of friends who are all into some kind of RPG/LARPing (role play games) kinda thing, I can't remember exactly but they took it in turns to "host" and find creepy places to play it. Girl A gets more geeky/gothy and the people she used to know don't really hang out with her anymore, so she just has her new friends. Girl B finds out that Girl A has gone missing and decides to try and find out what happened to her. She speaks to all of A's new friends and one of them decides to go with her to look I think. It turns out that it was A's turn to host their game and she found this abandoned factory (at least I think it was a factory). B goes inside to look for her and they find out that A slipped through some kind of hole while checking out the factory, broke her neck and died.

And that's what I remember of it. I'm pretty sure it's a YA/young teen book, not an adult book. Does anyone know what the heck I'm talking about? What is this book?!?! It'll haunt me for the rest of my days