Chester returns to the home of his estranged and hideously over-privileged family at Christmas, only to find an unknown killer disguised in a Santa outfit is stalking and killing family members one by one, in order to claim the huge family fortune. Which one of them is the killer?
When his housemate dies under mysterious circumstances, Nic Cross inherits a mysterious pyramid-shaped contraption left at the scene, unwittingly summoning a cult of wolf-people who dwell in the dark underbelly of London.