The Doctor tells Steven a story about himself and his granddaughter Susan. The Doctor and Susan have just been to the theatre and are lost in London. There is a heavy fog, and they cannot hear any signs of civilisation. When they double back, they are still lost. Flames start in the room, and Joan and her mother are burned up. The house disintegrates, and the Doctor and Susan rush for the door. Grandpa tries to stop them, and the Doctor yells for Susan to get the mirror. She breaks it, and Mr Calder collapses and scatters into ash.