Nell (Keira Knightley), Simon (Matthew Goode), and their son Art (Roman Griffin Davis) invited their closest friends to join their family for Christmas. As the group comes together, it feels like old times – but behind all of the laughter and merriment, something is not quite right. The most wonderful night of the year takes an unexpected turn when a poisonous cloud is descending upon the United Kingdom.
The world outside is facing impending doom, and no amount of gifts, games or Prosecco can make mankind’s imminent destruction go away. Surviving the holidays just got a lot more complicated.