Jack finished university three years ago, but he's still stuck in a dead-end job in a sinister call-centre in Manchester. When the beautiful (and rich) Jennifer comes into his life he thinks he has finally found his ticket out of there. Trouble is that his boss is interested in Jennifer as well, and there's something strangely bestial about him... So when Jennifer buys Fell House, a mysterious old mansion out in remote Cumbria, a house party on a legendary scale seems like the perfect escape. But as the party spins out of control on a seemingly neverending night, they must face up to the terrifying possibility that not all their guests may be human - and some of them want to feed.