It's Christmas, and for the first time in years the entire Birch family will be under one roof. Even Emma and Andrew's elder daughter, who is usually off saving the world, will be joining them at Weyfield Hall, their aging country estate. But Olivia, a doctor, is only coming home because she has to. Having just returned from treating an epidemic abroad, she's been told she must stay in quarantine for a week, and so too should her family. For the next seven days, the Birches are locked down, cut off from the rest of humanity, and even decent Wi-Fi, and forced into each other's orbits