Disclaimer: Sadly, I do not own Doctor Who, and characters found therein, or even Nitro-9. That honor goes to BBC.

Being a devout Ace fan, I decided to find a way to bring her back to Doctor Who. This story, which will be a prologue to several different and unrelated stories, takes place after Martha has joined the Doctor and before Utopia, but the story will be going completely out of the show's range of 'truth', so it doesn't really matter. This is my first fic, so no flames, please. hides behind chair

The Rucksack

It all started one day when Martha was exploring the TARDIS. Nothing dangerous, violent, extra-terrestrial, or otherwise threatening had happened for a while, so the Doctor had given Martha the day to herself while he went off to who-knew-where in the inner reaches of the TARDIS muttering something about having a look at some faulty wiring. Whatever it was, it didn't sound very interesting to Martha, so she decided to spend the day wandering around her temporary home.

After investigating a great many rooms, some of which seemed to be bedrooms but most of which were closets or wardrobe rooms holding fashions Martha was sure had never been seen on Earth, she came across something in the back of a large closet that intrigued her. It was a black rucksack, somewhat scuffed-up but obviously much loved. When she picked it up something clinked, so she unzipped it and looked inside.

Nestled in the bottom of the bag, along with several old tapes and a few of what looked like out-dated patches of some kind, were six or seven metal cans, their silver shells blank and unlabeled. Each one had a plain white cap. When Martha picked one up, it was very light, as though it were empty. She was tempted to pull off the cap and smell it, but she decided not to. There was no telling what the Doctor kept in his TARDIS. She decided to find him and ask instead.

She left the closet, shutting the door behind her, and set off with the rucksack over one shoulder, calling the Doctor's name. Eventually she got a response and the Doctor walked out of a room filled with various obscure bits of scientific equipment. He was grinning hugely, and Martha decided he must have completed whatever mission he set out to accomplish.

When he saw what she was holding, however, his face paled and he pointed at the bag. "That bag." He said shakily. "Put it down. Now. Put it down and step away slowly."

Alarmed, Martha did as she was told. When she was safely away from the bag, the Doctor walked over to it, unzipped it, and peered inside. Apparently satisfied, he nodded to himself and closed the bag before turning to Martha.

"Where did you find this?" he asked, gesturing toward the rucksack.

"In a big closet, right off the main room." Martha answered nervously.

Unexpectedly, he laughed. "Oh, yeah, I did hide it there, didn't I? I wonder why she never looked there…." he seemed to be talking to himself, and his eyes grew sad. Then he shook off his mood and looked at Martha again. "Did you see those cans in there?" he asked. When she nodded, he continued. "Never open them. Ever. They contain a substance known as Nitro-9, a highly volatile mixture of various chemicals including nitroglycerin." He grinned. "Basically, it goes 'boom'. Really, really loudly. With lots of fire and smoke. "

"Is it yours then?" Martha asked. She had a feeling it wasn't, but she was curious. "Were you a …I dunno, a chemist or something, before?"

The sadness returned to the Doctor's eyes. "No, it's not mine. It belonged to my…a friend of mine. She used to travel with me, long ago. Lifetimes ago." He turned away from her and picked up the bag. She left him alone then, and went back to her room, feeling as though she had done something wrong but not knowing quite what.

TWO DAYS LATER

Martha was, once again, looking for the Doctor. She wanted to ask him where they were going next, and when they were leaving. Besides, she was worried about him. Ever since the incident with the rucksack two days earlier, he had been unusually withdrawn, and she often saw him staring into space, an expression of profound loneliness on his face. She thought it had something to do with the friend he had mentioned.

She wandered the TARDIS' corridors for a while before seeing light streaming from under a closed door near the end of the hall. She walked up to it and opened it slowly, trying to make as little noise as possible. When she got the door open far enough to see inside, she saw the Doctor sitting on a simple bed, in a room that looked like it had been pulled straight out of the 1980s. He was looking down at something in his lap, but she couldn't quite see what it was. She walked over quietly to stand behind him.

If he heard her, he gave no sign, instead continuing to stare at the thing he held. Martha could see now that it was the rucksack from before. The Doctor was looking at it sadly, as one might look at a photograph of an old, long-gone friend.

Eventually, Martha spoke. "Are you all right?" she asked softly. "Are you thinking about her? The girl with the explosives?"

"Yes." He said, just as quietly, and then added simply "I miss her."

Martha was overcome with a wave of sympathy for this man, who had lost so many in his time. She was struck by a sudden urge, and so, without thinking, she said "Tell me about her." She sat beside him on the bed and watched him carefully.

For a long moment, he didn't speak. Then, without looking at her, he began.

"Her name was Ace. At least, that's what everyone called her. She would have killed anyone who dared use her real name. She didn't even know I knew it. I never told her. I didn't tell her much in those days. I should have, and on some level I think I knew that, but I was much too sly back then. I wanted to hold all the cards, to know exactly what was going on while keeping everyone else in the dark. Even Ace, my closest friend. By the time I realized I needed to apologize, it was too late.

"She was very pretty, Martha. She had brown hair, and she loved messing around with it. Up, down, braided, ponytail, always something different. She had this jacket, too, that she always wore. Black, it was, with patches sewn all over it. I don't know where half of them came from. I never thought to ask. She had a very young face, and it was very expressive. She had a hard time hiding her emotions. They always showed. She didn't smile a lot, but, oh, Martha, she had the most wonderful smile. Her whole face just lit up, and you couldn't help but smile back. I guess I never really gave her a whole lot of reason to smile. Honestly, I don't know why she never left. Maybe it was just her personality.

"She was from the late 1980s, originally, but I found her in the far future, stuck on an icy trading-post planet. She had managed to cause a time storm in her bedroom while making her favorite explosive, Nitro-9. When I found her, she was a waitress on the planet she ended up on, perfectly adjusted, just as if she had been dealing with aliens and time travel all her life. Her biggest complaint was boredom, and the fact that she had no place to go, so I took her in. This was her bedroom while she was here. After she…left, I tried to find her room. I was going to empty it out, but the TARDIS wouldn't let me. She hid the room from me. I could only find it again when I had decided to leave her room alone. The TARDIS liked Ace a lot, you know. The old girl always did have great taste.

"She was young when I found her, Ace was. Sixteen, in fact, and she acted it. She wasn't surly, or rude, not really, but she could be temperamental. She had been though a lot, and it showed. She was very suspicious of anything that didn't feel right to her, but she was still open and friendly, for the most part. She was so loyal! She swore to me that she'd never leave my side, and she didn't. She was always right there, 'watching my back', as she put it. It didn't matter if I told her not to come-she'd follow me and manage to get thoroughly tangled in whatever I was doing. She was stubborn that way. She acted so tough, Martha, but underneath she was very insecure, at first. I had the privilege of watching her grow into a confident young woman, though she was always somehow so vulnerable, underneath it all. All it took was one word, one phrase, and she would crumble. I did that to her, once, to save her and myself. At the time, I thought I had no choice, but now I know I should never have done what I did. I could have broken her faith forever, but somehow she forgave me. I never apologized, though. I couldn't admit I had been wrong, not even to myself.

"I wish you could have met her, Martha. You would have loved her. She was fiery and loving and incredibly brave, and she never backed down from a fight. She had a love of life you could almost feel. Her anger could be incredible, especially if someone did wrong by her or her friends. She was fiercely protective, and I loved her like a daughter. Which is why I had to send her off, eventually.

"I knew she needed to be with other people, not just my cranky old self, so I persuaded her to let me send her to Gallifrey's Prydonian Academy. I first had to persuade the Academy to take her, of course, but that was easily enough done. The Academy is where young Gallifreyans go to train to become fully-fledged Time Lords and Ladies. She would have become the first and only human Time Lady.

"She didn't want to go, of course. She was much too loyal. Finally, she agreed to leave so long as I promised to return for her as soon as she graduated, and to let her stay with me for the rest of her life. I agreed wholeheartedly, and I meant it. I never got a chance to fulfill my promise, though. The Time War started, and I never saw her again. I don't even know if she fought in the War, or was sent back to Earth. I will never know.

"All of my companions have left me, Martha. All for good reasons, of course- falling in love, getting tired of traipsing around the universe, wanting to settle down, finding a cause worth staying and fighting for, even getting trapped somewhere I couldn't follow. Whatever the reason, they all left. They had their own futures to make. Ace was the one person who swore she'd never leave and meant it. She told me she had no past she was willing to return to, and no future she was willing to face without me. She was really going to stay with me, Martha, but I lost her in the end. I lost her and all the other Time Lords, in one fell swoop."

The Doctor's voice had held fairly steady while he was talking, but it broke on the last word. Martha had never seen him look so unhappy. She didn't know what to say, so she said nothing. She just laid her head on his shoulder and sat with him silently.

This story will have at least one sequel. It will be labeled as the sequel, of course. Ace will appear it, I promise.

Reviews would be lovely- If you want more story, I must have reviews!!