Wife and mother Nell (Keira Knightley) feels pressured to prepare and host a Christmas gathering for her large circle of family and friends. Yet as the party ensues, existentialism seeps into their merriment as the party-goers discuss the mounting global paranoia over a poisonous cloud descending upon the United Kingdom that could spell the end of humanity. Debut writer and director Camille Griffin puts a unique spin on the apocalypse genre, situating her narrative in a holiday setting.