An extreme adventure tour group headed by deep-caving expert John Palmer (Christopher Atkins) descends into a 2000ft abandoned salt mine, that was mysteriously closed down years ago after an unexplained disaster trapped all of the miners. They prepare for rock slides, black outs, cave-ins - whatever might threaten their journey and commence their descent into the depths. Upon reaching a mysterious cavern Marcel (David Palffy), Vincent (Colm Meaney) and the other members of the tour group reveal that they are in fact searching the mine for a rumoured cache of precious stones. Their attempt to hijack the expedition is soon forgotten as they are confronted with a terror that they could never have prepared for - an unimaginable swift, silent killer long hidden in the cavernous earth. Now trapped, divided and surrounded by frightening predators, the group must again band together to have any chance of survival