With the unpredictable Cash serving as their guide, adventurous couple Eric and Jennifer and their friends Yolanda and Viktor set off to explore an uncharted cave system in a remote part of Northern Australia. Thinking that they will be safe underground as a tropical storm approaches, their thoughts are proven wrong when the caves begin to flood and they find themselves trapped in there. As they fight for their survival, they come to realise that there is something else to worry about other than the rising water and falling oxygen levels, as the storm has also brought in a pack of dangerous and hungry crocodiles.