*A/N The initial idea of jumping along the Doctor's timeline is not mine, and has, I believe, been done by several authors before me. But let's also be fair- it was even done by the show itself with River Song. Either way, credits to all those who deserve for the initial idea. I also do not own Doctor Who or any of its characters; I only own my own OC and storyline. Story contains spoilers for the show.

Teresa was walking down the busy London street, humming to herself lightly as she headed back home after doing some much needed grocery shopping. She was also in a bit of a hurry because she wanted to be home in time to watch the final Doctor Who season 7 episode, which would be coming out today. She had no idea what she was going to do when it was over, and she would have to wait the agonizing few months until at least the specials came out.

She'd heard they'd just wrapped up filming, which saddened her a little. This was going to be Matt Smith's final time as the Doctor, and he'd definitely been one of her favorites. But she was also excited, especially since she'd heard rumors that John Hurt had been seen filming with Matt Smith and David Tennant, and the prevailing theory was that he might be the next Doctor or, even more exciting, the lost Doctor, the Doctor between Eight and Nine, the Doctor who'd fought in the Time War.

Teresa had just walked around the street corner that would take her home, when she paused, blinking her grey eyes. There, right in front of her, was a bright, Tardis-blue light, shimmering in the air from an apparently invisible source. She frowned as she examined it, glancing around.

But no-one else seemed bothered by the bright light- in fact, they didn't even seem able to see it as they walked around and even through the light. Teresa slowly walked closer, shifting her grocery bags into her left hand as she reached her right hand towards the light. Nothing happened and she shrugged, taking a step forward, thinking to simply walk through it.

She yelped as she felt a sharp tug, as though something had grabbed her insides and jerked them. Reflexively she let go of the grocery bags, dropping them as she felt her whole world fade away in a burst of blinding white light. No-one looked twice as the blonde young woman disappeared into thin air… as though they hadn't even seen her there before she was gone.

Teresa stumbled, clutching her head as she felt like it was going to explode. Whatever that light had been, it sure knew how to pack a punch and she vaguely wondered what had happened to make her feel so giddy. Shaking her head lightly to clear it, she glanced around and paused, frowning.

Where am I? She wondered as she looked around what looked like a dimly lit corridor. How on earth did I end up here? She pushed her blonde hair out of her face as she stared, around curiously. It smelt strange, wherever she was- almost like someone was cooking.

She slowly walked down one of the corridors and stopped, staring ahead blankly. There, in front of her, was a white horse, all saddled up but with no rider. Teresa blinked slowly as it turned to face her, and she said slowly: "Okay…"

She walked up slowly towards the horse, reaching out carefully. It whinnied a little before pressing its nose against her hand and she smiled. "Funny seeing you here." She commented as she began to stroke its neck. It whinnied happily as Teresa glanced around, and admitted: "Although, I'm not really sure where here is."

Teresa peered about again as she murmured thoughtfully: "It looks like one of those space-themed sets in Disneyland or Universal, although how I'm here is the question. I guess I could be dreaming, but then I was just going home from shopping so I can't be. Unless I dreamt that part too. Or, you know, I'm crazy."

The horse whinnied again and she glanced at it, pausing mid-pet. "Then again," Teresa muttered, "I am talking to a horse." It whinnied and butted its head against her leather jacket, making her giggle. She jumped, startled, as she heard a male voice call: "Rose? Mickey?"

Teresa frowned, hearing the oddly familiar names, as the familiar voice continued to mutter angrily: "Every time, it's rule one. Don't wander off. I tell them, I do. Rule one. There could be anything on this ship."

Teresa stared as none other than David Tennant appeared around the corner, dressed in his dark brown pinstripe suit with the brown tie, his tan trench coat, and finally the famous converse on his feet. He stopped abruptly when he saw her, his eyes also widening and his mouth falling open before he beamed.

Well, it is strange to see a horse in a house, or wherever I am, but then again what's David Tennant doing here? Teresa wondered, and then blinked as the man bounded over, calling cheerily: "Terry! Brilliant to see you again."

Teresa stood stunned as he hugged her happily, before pushing his arms off and backing away slightly in alarm. He blinked in surprise and she asked him confusedly: "I'm sorry, have we met?"

He stared at her, hurt flashing across his face for a moment before it was replaced with a sad look of understanding. "Terry… do you know who I am?" He asked slowly, and she nodded. He started to look somewhat relieved, until she pointed out: "You're a bit hard not to, David, you're a pretty famous actor."

His shoulders slumped a little, and Teresa watched curiously as he quickly pulled out his sonic screwdriver. "Um… are you filming? And is it okay if I'm here?" Teresa asked as he pointed the screwdriver at her and then looked at its readings. Teresa had to admit, it was incredibly breathtaking to see David Tennant right before her, acting as the Doctor and to see the screwdriver with her own eyes.

"You're even younger… this must be your first trip." He murmured, his eyes becoming even sadder as she looked at him curiously. He eyed her and Teresa felt somewhat uncomfortable under his scrutinizing gaze. They were distracted as the horse neighed, unhappy that Teresa was no longer giving it affection.

She smiled at it, patting it again while the man stared at them curiously. "Is it yours?" He asked her curiously, and she glanced back in surprise. "No, I just somehow got here. I assumed it was yours, but I guess not. Then again, since this is my dream I suppose it could be mine." She mused, and his face fell a little.

"Er, Terry…" he began, and she hummed, glancing back at him as she continued to pet the horse. "This isn't a dream." He told her, and Teresa snorted. "Sure it is." She replied confidently. "I'm standing in some space-themed room with a horse and David Tennant, dressed as the Doctor."

He started at the word, but she didn't notice as she continued blithely: "The only way this could not be a dream was if I won tickets to a tour of the Doctor Who set, and since that clearly didn't happen, this is a dream. Or I've lost my mind, but I like to think I'm sane… mostly."

His lips twitched a little at that, as though slightly amused, before his face fell back into a serious expression. "Terry, this really isn't a dream. And why're you calling me David?" He asked her, and she rolled her eyes. "Yeah, you'd say that since you're a dream. And it's your name, isn't it?" She pointed out and he grabbed her hand.

He pulled her away from the horse, turning her to face him and she did so, startled, while the horse whinnied in protest. He ignored it as he said to her seriously, looking her in the eye: "Terry, I'm serious. This is real, and my name is definitely not David."

Teresa's heart beat a little faster as she stared into the warm brown eyes of her idol, but what really caught her off-guard was how old his eyes looked. They were impossibly old, and while David Tennant had done an incredibly good job of portraying that feature, this was a whole new level. It was almost too… real.

She blinked, and said slowly: "Okay… so you're the Doctor." He nodded, and she went on: "So, in my dream it's the Doctor, not David acting as the Doctor." He almost groaned in exasperation as he said firmly: "Terry, for the last time, this is real."

She sighed as she pointed out: "This can't be real. You're not real, and how else do you explain that you know my name?" "You told me." He replied quietly, and Teresa scoffed. "Okay, now I know this is a dream. I never told you, so clearly that's a lie."

"No, really, you did tell me." He told her, sounding frustrated and Teresa replied sharply: "Look, I think I'd remember telling the Doctor, or David Tennant, or whoever you say you are, my name."

"Look, Terry, you really did tell me. How can I prove to you that this is real?" He demanded, sounding a little desperate now and she sighed. She felt bad- this dream person probably thought he was real and wanted to believe he was. She could remember similar things happening in Doctor Who episodes.

Patting his arm, she decided to humour him and told him gently: "Never mind. I believe you, that this is real." He looked at her skeptically before saying abruptly: "You're just saying that because you think I'm a dream-being that's upset to find he's not real, aren't you."

She blinked and muttered: "Okay, yes. That backfired."

He sighed and looked at her thoughtfully before asking: "How did you get here?" She stared at him, and he repeated impatiently, hoping it would make her realize this was real: "Terry, how did you end up on this spaceship."

"We're on a spaceship?" She asked in surprise, and looking around curiously. Wow, I must've watched too much Doctor Who if I'm dreaming of being with him on a spaceship. She mused. The Doctor interrupted as he said impatiently and a little anxiously: "Yes, you're on a spaceship, not important right now. How did you get here?"

"Well," Teresa began, "I was walking home from the grocery store and found a bright blue light on the street. I touched it and…" She shrugged, gesturing around her to indicate the ship, but the Doctor said quickly: "Did anyone else see you, or the light?"

Teresa frowned as she replied slowly: "No, they didn't. Why?"

The Doctor took a deep breath as he placed his hands on her shoulder and told her softly: "Terry, you were transported here from your universe. That blue light, it brought you here and will continue to transport you through time and space and land you in different times of my life, my past and my future."

She stared at him and asked slowly: "We never meet in the right order?" He nodded, looking hopeful again although his tone was sad as he confirmed: "Never."

He was surprised when she snorted again as she muttered: "Mm, guess my mind isn't that original."

He stared at her, his hands dropping to his sides, and she sighed. "'Never meet in the right order'? Now, why does that sound familiar?" She asked sarcastically, although it was mostly directed at herself. He frowned, confused, and asked: "What?"

Teresa sighed as she replied: "Never mind, not important right now."

"No, this is important, why won't you believe me when I say this is real?" The Doctor demanded, sounding irritated now, and she pointed out: "Look, if you ended up on a spaceship with a horse and an alien from your favourite TV show, would you believe them? At least make the dream somewhat believable if you're going to argue that it's real."

"It's really not the strangest thing to find a horse on a spaceship when you're with me." He retorted, and she blinked. "And am I really your favourite TV show? You never mentioned that before, just that there was a show somewhat similar to my life." He rambled, when she interrupted.

"What?" She asked, and he repeated confusedly: "What?" "No," Teresa clarified, "what you just said. Horse on a spaceship?" He nodded, looking a little confused as he replied: "Yes, we're on a spaceship."

Teresa's eyes lit up and he looked hopeful until she asked excitedly: "Oh, is this 'Girl in a Fireplace'? That is awesome, although I'm not a fan of how it ends. Can I meet her? Reinette? Oh, and does that mean Rose is here? Always wanted to meet her."

The Doctor stared at her sadly, before he gave her a soft smile and murmured: "Sure." She beamed, when something else he'd said registered in her mind.

"Hang on, you said I told you before that there was a show 'somewhat' similar to your life?" She asked and he nodded.

"Right after we… I met you for the first time." He told her softly, and Teresa frowned.

"What does that mean? And what do you mean 'somewhat'?" She asked, and he hesitated. The Doctor stared into her grey eyes for a minute, as though searching for something, before he took a deep breath. She watched him warily, and his lips curved into a small smile when he saw her look.

"Terry." He said quietly and her heart almost stopped. It was one thing to hear him say her name; it was another thing entirely for him to say it so sincerely, in that low tone that made her heart race. Teresa swallowed and asked just as quietly: "Yes?"

He smiled a little, taking her hands in his as he told her gently: "I know you don't believe me now. But just listen and keep this in mind until you do. You were transported into my timeline, and for some reason we never meet in the right order. So, there are times when I know more about you and lots more times when you know more about me."

She frowned but he explained: "You told me that there is a show back in your universe that is about my life. You've seen it, and so you have foreknowledge on much of my future. But, that show isn't real, not exactly, so there are times when things go differently. Sometimes very differently."

The Doctor paused to see she understood, so Teresa nodded slowly. He continued softly: "But sometimes, it goes as how you remember seeing. And Terry, you need to remember this: foreknowledge is dangerous. You're always careful in the future, your future, not to give too much away. 'Spoilers' as you call them. So keep that in mind, no matter how much I sometimes might bug you, you can't let me know about my future. You understand why, right?"

Teresa nodded slowly again, now slightly afraid. He sounded so… serious. And he spoke of her jumping across his timeline, that he'd seen her in his past and what he claimed was her future. She wasn't entirely convinced this wasn't a dream… but now there was a sliver of doubt. What if it wasn't? What if this was real?

In any case, Teresa resolved not to tell him about how she knew this episode would end. Just in case. And even if this was a dream, she wouldn't want to accidentally alter his timeline and cause him to die or cause the universe to explode or anything. The Whovian in her refused to let that happen.

The Doctor smiled at her, and pulled on her hands, leading them off as he said cheerfully: "Now, you said you wanted to meet Rose, so let's get you introduced. We need to look for Rose and Mickey first though. They've wandered off, despite my orders for them not to."

"Why're you surprised? Since when do they, or anyone really, listen?" Teresa teased and he grinned. "You have a point." He admitted and she laughed as they walked off, the horse following them.