Vampires

Vampire horror. When five couples respond to an advert to take part in a 30-day trial for a medical company, they are taken to an old castle and told that they cannot have any contact with the outside world or they will forfeit their 20,000 pounds prize money.

The group agree, confident of winning the money, but shortly after their arrival, unexplainable events begin to occur in the house.

At first the challengers dismiss it as a test of their nerves by the organisers, but events soon take a sinister turn and the group are forced to fight for their survival with the castle's other inhabitants.