The Doctor is alone, powerless and terrified, on the leisure planet Midnight. Soon, the knocking on the wall begins. As paranoia turns into a witch-hunt, the Doctor's greatest strengths are turned against him, and a sacrifice must be made…
William fears things with Mary are ruined, but she's preoccupied with a truant teenager and her meddling mother, Molly, who's got "fix up" plans of her own.
