After a tragic accident, six friends reunite for a caving expedition. Their adventure soon goes horribly wrong when a collapse traps them deep underground and they find themselves pursued by bloodthirsty creatures. As their friendships deteriorate, they find themselves in a desperate struggle to survive the creatures and each other.
- Year: 2005
- Country: United Kingdom
- Genre: Adventure, Horror
- Studio: Pathé, Celador Films, Northmen Productions
- Keyword: mutant, expedition, cave, claustrophobia, trauma, darkness, panic, rope, climbing, appalachia, friends, gore, female protagonist, best friend, creature, survival horror, grieving, speleology, brutal violence
- Director: Neil Marshall
- Cast: Shauna Macdonald, Natalie Mendoza, Alex Reid, MyAnna Buring, Saskia Mulder, Nora-Jane Noone