Starring: Shauna Macdonald, Natalie Mendoza, Alex Reid, Saskia Mulder, Nora Jane Noone, MyAnna Buring

Once year after a tragic accident, six girlfriends meet in a remote part of the Appalachians as part of their annual extreme outdoor adventure, in this case an exploration of a cave hidden deep within the woods. Far below the surface of the earth, disaster strikes, and there is no way out. The group splinters and each woman pushes on, praying for another exit. But there is something else lurking under the earth. As the friends realize they are now prey, they are forced to unleash their most primal instincts in an all-out war against unspeakable horror.