Jill, her three sons, their wives and children are driving in convoy on Christmas Eve. But something sinister is simmering behind their happy smiles. Mimi is struggling with her new twins, but at least a glass of wine smooths out life's jagged edges. Andrea's starting to wonder if her marriage is as happy as she'd thought. Darren is reeling from a surprise request and teenager Callie has become increasingly withdrawn. On the way to their holiday house, a terrifying car accident devastates them all. But someone unexpected was in one of the cars. No one is searching for them. And their time is running out