"Good morning, Doctor," said the Brigadier, walking into UNIT's laboratory to find the Doctor experimenting on some highly advanced technology, as usual.

"Oh, good morning, Brigadier," said the Doctor, briefly looking up from his work, only to return to it in the next instant.

"I see you're still tinkering with that machine of yours. Any luck?"

"Tinkering?" said the Doctor, quite agitated. He put down the tools he was holding in his hands and glared at the Brigadier. "I don't tinker, Brigadier. This is a highly difficult procedure, and I would appreciate the utmost silence while I work. Now, if you'll excuse me..."

"A bit touchy today, aren't we? You're not over Miss Shaw's leaving yet, are you?"

"Liz chose to leave. I wouldn't hinder her wishes. Now, please don't hinder mine."

"Sir?" said Sergeant Benton, no one even noticing he had even entered the lab. The Doctor grunted, totally giving up on the idea of being able to get back to his work in the near future.

"Yes, Sergeant?" said the Brigadier.

"There's a woman... She.. well..." Benton stammered. The situation was a little too confusing for him, so he didn't know quite how to put it into words.

"What woman?" asked the Brigadier. "Out with it."

"She says she works for UNIT, but I've never seen her before. She says she's from the future."

"Future," said the Brigadier, a bit annoyed. Must be some sort of practical joke, which he had no time for today. "That's utterly fantastic. How could she be from the future? She's obviously out of her mind."

"I don't know, Brigadier," said the Doctor, who had calmed down with the peeking of his curiosity. "I'm not one to judge those who contend being from a different time. Let's have a talk with her."

"Well, that's just it, Doctor," said Benton. "She wants to talk to you. She says she knows you."

"Really? Who did you say she was again?"

"All she said was that she's UNIT's scientific advisor. I told her that was impossible, since you are. She said she's from later on. She was very insistent on talking to you."

"Well, best bring her here then, aye?" said the Doctor.

"Sir?" asked Benton reluctantly.

"Best do as the Doctor says," said the Brigadier. "Bring her in, Sergeant." The Brigadier stood still, staring at the swinging door as the sergeant left. The Doctor leaned back in his chair and crossed his arms as he waited for Benton to return with the so-called acquaintance.

Moments later, Benton returned with a pretty, young woman with dark, pixie hair and large, curious eyes. The Doctor knew her instantly; he knew her two minutes before instantly even. "Susan?!" he gasped.

"Grandfather!" shouted the woman, running into his arms and gripping tightly around his waist. She buried her head in his shoulder as she sobbed. The Doctor returned her hug and stroked her hair. My how she's grown...

"My dear Susan!" said the Doctor, still in disbelief. "Whatever are you doing here?"

"The Time Lords, they found me," said Susan, raising her head to look at his face, so different than the one she knew. But the glint in his eyes was unmistakable. "They told me you were here. They let me see you after I insisted. I only have a little while before they transport me back to the 22nd century."

"Doctor," interrupted the Brigadier. "Did she just call you what I thought she called you?"

"If you mean 'Grandfather,' then yes. Susan is my granddaughter."

"I didn't know you had a family, Doctor," smiled Benton. "Pleased to meet ya."

"Oh, yes," said the Doctor, suddenly remembering his manners. "Susan, this is Sergeant Benton. And this is Brigadier Lethbridge-Stewart. But how did you introduce yourself before? Benton says you're UNIT's scientific advisor."

"Well, Grandfather," explained Susan. "After you left David and I together, UNIT found and recruited me. They said I could be of great service to them. Well, I took on the job. While David helped rebuild London, I helped UNIT with extraterrestrial matters. It's funny, I didn't realize until a few months into the job that you used to work here, too. Of course, I didn't know you were in exile; I just thought you were doing it to be helpful. Then, when the Time Lords finally tracked down my location, they told me you had been put on trial and sentenced to exile on Earth."

"Trial?" said the Brigadier, raising an eyebrow. "We shall have to have a little talk, Doctor."

"Yes later, Brigadier. Later." The Doctor turned back to Susan. "But did they harm you in any way?"

"Oh no. They said they had no grudge with me. It's strange though, seeing's how I'm breaking the First Law of Time by helping out UNIT so blatantly."

"Yes, well, that's because of me," said the Doctor, touching his fingers to his lips in thought. "I worked out a little deal."

"What kind of deal?"

"You see, the original judgment would have been execution. The Celestial Intervention Agency, however, stepped in behind the scenes to lower my punishment."

"The CIA?" asked Susan. "But why should they help you?"

"Oh, for many reasons," sighed the Doctor. "Mostly so they could use me whenever they need to. I'm a renegade, so I'm expendable."

"But they can't force you!" insisted Susan.

"Oh, yes they can. I'm utterly helpless without the use of my TARDIS. And well, I couldn't let anything happen to you."

"Me? What do you mean, Grandfather?"

"Do you think I would have left Gallifrey the way I did if it wasn't for you, Susan?" said the Doctor, holding Susan at arms length so that he could get a better look at her. "If anything should ever happen to you... Well... You're all I've got, you know."

"Oh, Grandfather!" sobbed Susan, hugging him tightly again.

"I've missed you, Susan."

"I've missed you, too. I didn't know what had happened to you: if you were alive or dead, if the Time Lords had finally found you or not, if Ian and Barbara were still with you."

"Ian and Barbara?" the Doctor chuckled. It had been a while since he thought of those two. "Oh, they left me ages ago. Went back home. They're perfectly alright. And so am I, for the most part anyway. I'm not so helpless as you think. I can manage on my own without you watching out for me. I wanted you to get on with your life, remember?"

"Oh, I know that, Grandfather," said Susan. "And I love David, and our home together. But, sometimes, late at night, I look out into the stars and wonder if you're there, making new acquaintances, saving those who can't save themselves, getting yourself into trouble... "

"He's managed to do all that right here," mumbled the Brigadier to himself. The Doctor gave him a menacing look, but said nothing.

Susan felt a slight tug. "Oh, I think they're sending me back now."

"Alright, Susan," said the Doctor. "Best get back. I'll be just fine here."

"Are you sure, Grandfather?" asked Susan. "Perhaps I could ask for an appeal?"

"Oh, no," said the Doctor. "That won't be necessary. They'd never change their minds about me. No, I'm afraid I'm stuck here indefinitely. But I'm working on repairing the TARDIS, so don't worry."

"But you've been trying to repair the TARDIS for ages!" protested Susan. "And I can see for myself that the chameleon circuit is still broken."

"Yes, well... it has kind of grown on me," said the Doctor, looking at the blue police box. "Yes, I rather say I quite like it. It suits me just nicely."

"Well... if you say so, Grandfather." Susan wasn't one to usually argue with the Doctor, and she supposed she just had to trust him where this matter was concerned. And suddenly she felt another tug, and the world sort of faded away for a moment.

"It seems you'll be gone soon," said the Doctor. "It was good to see you. I'm so happy you've been able to settle down and make a home."

"Well," said Susan. "I always did like Earth."

"Yes," mused the Doctor. "I've been able to see what you've been talking about. I rather like this planet myself now."

"Oh, I'm so glad," said Susan, closing in for one final hug. "I love you, Grandfather."

"I love you too, Susan," said the Doctor. "Take care of yourself."

"Of course," she said. "I've learned from the best." And then she vanished.

The Doctor sighed and sat down in front of his work again. He was no longer in the mood, though.

"Well..." said the Brigadier, uncomforted by the sudden silence. "That was a surprise."

"You could say that again, Brigadier," the Doctor agreed.

"Well, I suppose I'll get back to duty now," said Benton. He'd had enough for one day, and was just hoping there'd be no sign of some alien menace today. He left the Doctor and Brigadier alone again.

"Oh, and Doctor," the Brigadier said, recalling a thought. "Tell me about this exile of yours."

The Doctor slumped even further down into his chair and groaned. This was going to be a long day...