Sanctum by Madeleine Roux

Sanctum picks up right after the terrifying and transmuting experience from Brookline. Dan, Abby, and Jordan try to move past their crazy involved summer after almost dying in the last book but someone else has an other idea. They still have nightmares from the awful place and They have received old carnival photographs as well, with the words “You’re not finished” on it. It's an amazing thriller and it keeps you extremely interested. I really enjoy that it picks right back off where the left off. I love the friendship, the real life application, and the creepy horror along with it.