The tale unfolds in contemporary England during a late and snowy December, with a young married couple, Jonah (Stephen Campbell Moore) and Elaine (Eva Birthistle), journeying into the country to spend New Year's with immediate family - Elaine's sister Chloe (Rachel Shelley) and brother-in-law Robbie (Jeremy Sheffield). Accompanying the adults are three children: Casey (Hannah Tointon), Elaine's adolescent daughter from a first marriage (who resents being dragged along), and youngsters Paulie (William Howes) and Miranda (Eva Sayer), her children with Jonah (who can't wait to see their cousins Nicky and Leah). Upon arrival at Robbie and Chloe's home, ominous and increasingly bizarre events begin to transpire.