Benedict is an inventor whose life's work is a clean energy machine. It has just made him an overnight sensation and his family is suddenly wealthy. Benedict's wife, Karen, and his teenage daughters, Charlotte and Poppy, are proud of him. But there are problems Benedict is too busy to see: Karen is deeply unhappy in the marriage and contemplating an affair, Charlotte, who is dealing with a chronic illness, is growing more and more distant, and Poppy is cracking under the pressures of her social circle. And there's another problem. Benedict holds a rather terrible secret about his clean energy machine. Then, on Halloween night, an accident threatens to make everything far worse for the family. The accident kicks off a series of hauntings in their beautiful, historic home in affluent Belgravia, and the ghosts make it clear that they want something from them. Karen has to save her daughters -- and herself. Meanwhile, Benedict is consumed by the knowledge that he has to achieve the impossible by Christmas. As time ticks ever closer to the revelation of his secret, he spirals further into despair . . .