The Doctor's Granddaughter
"During all the years I've been taking care of you, you in return have been taking care of me. You are still my grandchild and always will be. But now, you're a woman too. I want you to belong somewhere, to have roots of your own. With David you will be able to find those roots and live normally like any woman should do. Believe me, my dear, your future lies with David and not with a silly old buffer like me. One day, I shall come back. Yes, I shall come back. Until then, there must be no regrets, no tears, no anxieties. Just go forward in all your beliefs and prove to me that I am not mistaken in mine. Goodbye, Susan. Goodbye, my dear."—The First Doctor, The Dalek Invasion of Earth
"Doctor, where are we?" asked Clara as the TARDIS landed.
"We're on Earth," replied the Twelfth Doctor. "Earth, circa 2274. The Daleks invaded a century ago, and I want to make sure that human history is back to normal."
"Is there another reason?"
"Remember how I said that I brought my granddaughter to the festival on Akhaten?" he asked. Clara nodded. "I left my granddaughter here a century ago so that she could have a life of her own with one of the locals here, a man by the name of David. After all these years, I've finally found her."
"How?"
"Easy, my dear," responded the Time Lord. "I simply scan for non-human DNA, and there it is, approximately 5 kilometres from our current position, about 50 metres up. She must be in a building."
"Why didn't you just scan for two hearts?" asked Clara. "I mean, she is your granddaughter."
"People from Gallifrey, that is to say Gallifreyans, are born with only one heart. The second only comes after the first, or sometimes second, regeneration."
"Are we gonna walk?" the Impossible Girl asked.
"Do you still have your motorbike?" countered The Doctor.
\\/
"Ms Foreman, there's a man here to see you," said a nurse to an old woman in a hospital bed. "He said something about being The Doctor."
"Go away, Nurse Chapel. No more Doctors!" the woman shouted.
A man walked into the room past the nurse. "The nurse didn't say 'A Doctor,' she said, 'The Doctor' and that's me. The definite article, if you please."
"Grandfather?" asked the frail woman. "Is that really you?"
"I told you that I'd be back, one day," said The Doctor. "You're time-line was in flux so badly that the TARDIS couldn't lock on to you until now."
"Which one are you? Three, four?"
"Don't you remember?" asked The Doctor. "You've met them before, and they didn't look like this. No, the Time Lords owed me a favour, and here I am: Number 13."
"He still calls himself the 12th Doctor, though, due to a little mishap with the Time War," butted in Clara.
"You helped to steal the TARDIS," exclaimed the old woman in her frail voice. "You told Grandfather which TARDIS to steal."
"Another me, perhaps." said Clara. "I was born to save The Doctor, and I sent myself along his time stream to help him out."
"My time is running out, Grandfather," said Susan.
"Not necessarily," stated The Doctor, pulling out the TARDIS key. He held it for a minute, and suddenly, there was a whooshing sound, and the TARDIS materialised around them.
"You've redecorated," stated Susan. "I don't like it. I preferred it the old way: white with the round things. What happened to all the round things, Doctor?"
There was a glow of yellow energy from the Time Rotor.
"What's happening?" asked Clara as the yellow glow seemed to surround Susan.
"She's not been around long, has she?" Susan asked as she collapsed to the ground.
"It's just she's never seen a proper one before, and you're doing things the old fashioned way."
"I'm regenerating, Clara. Now you take good care of The Doctor, got it?" stated Susan. The glow surrounded her, and she started to scream. Her face and other features started to change. After a minute, a new girl was standing in place of the old woman. She was about 1.7 metres tall, had green eyes, ginger-coloured hair, and a very nice body.
"Legs, I've still got legs. Hands, hair, eyes. Oh, I'm ginger!" she said.
"Don't rub it in," muttered The Doctor.
"That's a new voice, too!" she exclaimed.
"CONTACT!" said The Doctor and his Granddaughter as they ran at each other, hitting their heads together.
"I look like one of your old companions," she said. "Well, not a companion but someone you helped out. Does Wibbely-Wobbely, Timey-Wimey ring a bell?"
"What did you just do?" asked Clara. "Why couldn't she regenerate before?"
"We're Time Lords. We simply downloaded each others memories, to use the 21st century term." answered The Doctor.
"A Time Lord needs some help to start the first couple of regenerations," responded Susan. "As the TARDIS was gallivanting around the galaxy for, what 2000 years?, then I couldn't regenerate. Now, Doctor, when can we go home?"
"I'm sorry, Susan. I'm so so sorry," replied The Doctor. "Gallifrey is gone. Me, me and me put it into another dimension, like one of those stasis cubes. It was the only way to save the universe from the Time War, and by extension, the Daleks."
"You've met up with other versions of you?" asked Susan.
"You came with me once," he replied. "I've met myself so many times. One time, it was for the funeral of one of my later Companions, a Brigadier in UNIT. Most of the time, there was an enemy that was just too hard for one of me to defeat. Lets see, there was Omega, the Lord President, a big group of enemies that included the Sontarans, myself (I forgot to put the shields up), and last but not least, the Zygons, in association with the Daleks and the Time War."
"The Time War?" asked Susan, and The Doctor explained, as he pulled the lever to take off and fly off into the galaxy.
A/N: Susan's regeneration is a combination of the old and the new styles, she regenerates into a form similar to Sally Sparrow. I chose that form as an in-joke to Inspector Spacetime, as the actress, a Carey Mulligan, supposedly played one of the 'Associates' (the IS word for 'Companion')
The multi-Doctor stories mentioned:
Omega: The Three Doctors
Lord President: The Five Doctors
Sontarans, et al.: The Two Doctors
Shields: Time Crash
Zygons, et al. Day of the Doctor