The queen of YA thrillers is back, and this time, it's a fight to survive.

In Piper's hometown, teenagers keep disappearing, and everyone assumes they're just a bunch of runaways. But when yet another person disappears, Piper and her best friend Hazel suspect something more sinister is going on.

So they decide to investigate, determined to learn the truth. Their search for answers leads them to the source of the missing people...and their captors. Piper and Hazel suddenly find themselves locked away in a secluded building in the middle of a privately owned forest.

But the building isn't only meant to keep them imprisoned; every room is a test to see if they can make it out alive.

And failure means being lost...forever.