You may think you can hide away in dreams. Safely tucked up in bed, nothing can touch you. But, as every child knows, there are bad dreams. And bad dreams are where the monsters are. The Doctor knows all about monsters. And he knows that sometimes they can still be there when you wake up. And when the horror is more than just a memory, there is nowhere to hide. Even here, today, tonight... in the most ordinary of homes, and against the most ordinary people, the terror will strike. A young boy will suffer terrifying visions... ...and his family will encounter a deathless horror.