Seven friends arrange a weekend meet up at a secluded holiday house, after not seeing each other for a long time. Unfortunately for them, a fiery sink-hole has opened up in the mountains nearby and it's spewing out sulphur and causing a nauseating stink outside. They might be confined to the house, but they are determined to have a good time. As the weekend progresses, some of the friends start behaving out of character and experiencing worrying events. It's too late when they realise that it's not just a sink-hole that opened near their isolated retreat, but something altogether more horrific and a malevolent presence is stalking them.