As Clara browsed through the TARDIS library, her arm accidentally knocked a small wooden box carved with circular Gallifreyan. As it hit the ground, the lid came off and an old piece of paper slid onto the floor. "That's old," Clara muttered, picking up the paper, "that's really old". She noticed some faded writing on it, it was only just visible. She looked closely at the words:

Dear Grandfather

I do hope this letter finds you well; it has been quite some time since we last spoke. 3 years and 48 days to be precise. During that time, I have now become Mrs Susan Campbell and I am expecting fraternal twins this coming December. I have enclosed some photos of my wedding and the ultrasound picture of your future great-grandchildren. We plan to name the girl Elisabeth and her brother Thomas. I miss being on the TARDIS with you, I love David and my new family but being pregnant and married life at home is very mundane and dull compared to our time together. Have you visited Gallifrey since our exile? How is the TARDIS? How are Miss Wright and Mr Chesterton? I'm sorry to pester you with all these questions; you may not even receive the letter for I have been told that the Intergalactic Post Service has been quite unreliable recently. I am in my second trimester of my pregnancy presently and so far things have been going alright. Unfortunately my back is starting to ache because of the strain that the twins are putting on me and I have been getting the occasional nosebleed but aside from that all has been going smoothly. Do you have any photos of when I was younger? I meant to check the TARDIS data base but I never really remembered to. David and I have a comfortable house suitable for our new family (That reminds me, thank you for setting me that universal savings account up when we first left Gallifrey) and we live and love well.

Your grand-daughter

Susan x

Clara folded the piece of paper and carefully put it back in the box and placed it on the main table in the library. "Susan, why does that name sound so familiar?" she said to herself.

"That's because she's my grand-daughter." A voice came from behind her. The Doctor was leaning against a shelf with an annoyed look on his face.

"Doctor, how long have you been here?"

"Long enough to see you read my letter." The Doctor took it out of the box and tucked it into a pocket on the inside of his jacket. "Why did you read it?"

"I was curious."

"About what?"

"I dunno," Clara shrugged, "I just was."

"Well, that letter was private. Don't go through my belongings again." The Doctor grumbled and turned to walk away.

"Have you visited her?" Clara asked. The Doctor stopped and turned to look her in the eye.

"No." he said sharply

"Why not?"

"Because it would be too hard."

"How?"

"It just would be. Now stop asking questions and go somewhere else." He stormed out of the library.

Clara waited for a moment and then followed him in silence until she had reached the control room. He was sitting down on gently holding the letter in his hand up to his chest. After a minute he sighed and put his head in his hands. Clara hadn't seen this version of him this emotional. "What do you want Clara?" he looked down at her at the bottom of the stairs.

"Visit her." She said simply, "She'll be waiting for you."

"And what if I'm too late?"

"What do you mean?"

"I promised that I would come back. What if I didn't come back soon enough and she won't want to see me?" Clara had seen the Doctor afraid and vulnerable before but not in this way.

"She will want to see you. It's better late than never."

"But what if she doesn't?"

Clara marched up to him and looked him in the eye seriously, "Doctor. Stop these 'what ifs' and visit her. The Doctor looked away from her sadly. "I'm sure the TARDIS misses her."

The TARDIS made a noise that communicated that it agreed with Clara, "See. Of course she misses Susan. You might be her thief but you're forgetting that Susan was your accomplice too. Susan means just as much to the TARDIS as she does to you."

The Doctor smiled at Clara, "You know what? You're right." He hugged her, "Thank-you Clara Oswald."

"I'm always right; I thought that you'd know that by now." She laughed and hugged him back.

The Doctor ran to the console, almost skipping, and punched in coordinates to London, 22nd century.

As soon as they had landed, a young woman with short black hair and brown eyes ran into the TARDIS. She stopped as she saw the Doctor and Clara. "Grandfather?"

The Doctor grinned and pulled her into a tight embrace, "I've missed you Susan."

Susan giggled, "My word. You look younger than me!"

"How long has it been?" the Doctor asked as he stepped back.

"I've just had the twins." Susan smiled, "Come on, David will be happy to see you and to meet …" she looked at Clara, "I'm sorry, what's your name?"

"I'm Clara," she replied, "Clara Oswald."

"Well it's lovely to meet you Clara." Susan pulled the Doctor out of the TARDIS by his hand, "Come on then, we have lots to talk about."

Clara stayed back for a minute and smiled. The Doctor looked so happy, happier than she had seen in a long time. Her work for today was done.

How was that? Alright? Rubbish? Good? Feel free to let me know :) Did any of you spot the little reference to Tom Baker and Lis Sladen?