[In the life of the Doctor there are good days, and there are bad days. Sometimes, when he's feeling down, the TARDIS (who has a very long memory), takes over the viewscreen and reminds him of the good days.]
The old man strode into the TARDIS, his walking stick clicking against the tile floor with every other step. He was already in heated conversation with a young girl dressed all in grey from her cap to her trousers.
"…could have been killed! Really, Susan, this is why I don't let you go off by yourself," the Doctor said. He hung his Astrakhan on the stand by the door.
"But Grandfather," the girl protested, "the Grand Vizier was torturing the peasants for information about us! I couldn't just stand by and let innocent people be tortured!"
"My dear, they were not innocents," the Doctor huffed. "They were pirates and thieves. Scoundrels, to the last man." He moved to the console and began commencing dematerialization. "Come on, give me a hand."
"Still, Grandfather," Susan replied as she began running calculations on their space-time trajectory, "they had nothing to do with that Krilitane conspiracy. I had to give myself up! Set a vector of 28 by 17 degrees south," she added, reading off her calculations.
"Yes," the old man replied, as he set their course accordingly. "and a fine mess it got us into, too. There," he stepped back from the console, "temporal orbit established." He looked over at Susan, who was gazing at him respectfully, yet also with defiance.
"I had to save them," she said quietly. As he looked at her, the Doctor could not help but notice how much she was growing to resemble her father. He had been a good man, and a most satisfactory husband to his daughter until a sudden plague took both their lives.
The Doctor sighed. "I know, my dear. Of course you had to. It is because you are compassionate, just like your mother." He moved to one of the seats and patted the space beside him, inviting his granddaughter to join him. "Have I ever told you about when I traveled with your mother?"
Susan shook her head mutely as she crossed to the seat beside the Doctor, her expression curious but hopeful. Susan had barely known her parents, and was eager to hear more about them.
"It was a very long time ago," the Doctor began. "I was much younger then, and we were crossing the heartlands on foot."
"The heartlands!?" Susan exclaimed. "That wilderness? Whatever were you doing there?"
"It isn't important," the Doctor said. "Anyway, we were travelling, and we came across a boggy clearing. It was very much like the surface of Quarn 3, all dusty and covered in briars and thorns. I made a comment about how that area ought to be burned clear by the council and developed. Your mother—she was only about 45 at the time—took my hand in her little one and pulled me along, over thorns and brush and scrub, and pointed to a little pool of water. Around it was a whole bustling community of squish bugs, all vibrant red and blue and green. She looked up at me with her big, brown eyes, pointed to them and said, 'Why would you want to take their homes?'
"That was your mother all over. She was always seeing beauty and goodness where I- where others- only saw filth. And you are much the same, my dear, aren't you?"
"I'm sorry for causing you so much trouble, Grandfather," Susan said meekly.
"Not at all, my girl," the old man smiled. "You have a special gift. Use it, whatever trouble it may cause me." The Doctor stood up. "And now it is time you got to bed, Susan."
The young Gallifreyan rose, too. "Thank you for telling me the story," she said, kissing him on the cheek. "Goodnight, Grandfather. I love you."
"And I love you, too," he said.
After Susan had left the console room, the Doctor lit his pipe, sat back down and mused for a while.
"She's got real promise, you know," he said aloud. "But she needs training. She needs to learn how to blend in, to understand other species, and especially to be more careful." The Doctor stood and crossed to the controls. "I don't know if you can hear me, time capsule," he said. "I don't know if you like Susan's name for you." He tried the name out consideringly. "TARDIS… Please, if you can hear me, find my granddaughter a good school." More quietly, he added. "Find us some good teachers."