He should have known the minute his back was turned Rose would go and find herself another pretty boy to drag along with her. The whiz kid in Utah had been bad enough, what with him passing out at every little thing and implanting ports into his head so he could have access to all history everywhere, now she had to bring a Time Agent with her. A pretty, suave, charming Time Agent.

The Doctor hated Time Agents.

In all fairness, most Time Lords hated Time Agents, or at least they had when they had been around to care. Human beings finally got smart enough, eventually, to create their own time travel devices, and so with all the thundering enthusiasm and bumbling clumsiness of any children, ventured off into all of time and space to see what sort of messes they could make. And when there were Time Lords, and when they could catch them, they would at least try to clean them up and curse the day that humans learned that particular trick. At least in some point in the future, after a century or two of realizing just how bloody difficult it was to keep track of timelines and how devastatingly intelligent one must be to understand the true beauty and complexity of time and space, humans eventually give up the enterprise, which in the Doctor's opinion they shouldn't have been in anyway without having the right sort of brain for it, (and perhaps he had manipulated and tweaked here and there to aid to its demise).

He'd never liked the agency or their agents. The very secret nature of the Time Agency bred dishonesty and amoralism on a shocking scale. For all their many faults, and there were plenty, that was one thing the Time Lords hadn't suffered from. Manipulative and conceited, he'd found traces of Time Agents and their meddling for centuries. Which was perhaps, out of gut instinct, he hadn't particularly liked Jack Harkness. That, and his callous, con artist's attitude to something as dangerous as a Chula warship. Idiot playing with fire, he was, cock sure and out to make a buck at others expense. It certainly wasn't because of his truly astonishing good looks or the way that his smile made even the Doctor go a bit weak in the knees. Or the way Rose turned giddy around him, batting her mascara-caked eyelashes at him. That certainly wasn't it at all.

"You don't like Captain Jack much, do you?" She was settled in an old wheelchair, shoved into the storage room they now hid in, rocking it back and forth with her feet, twirling strands of her hair between her fingers. She was bored, despite the truly magnificent music on the radio, and watching him poke about the bars at the window of their makeshift prison with his sonic screwdriver.

"Why should I not like him? I've only just met him."

"You are such a horrible liar," she snorted, the chair creaking slightly as she gave it an extra bit of a shove.

"Now look who is hurling insults," he mocked, barely turning to look at her.

"You are the one judging a man you say you've just met."

"Now don't go putting words into my mouth," he warned, fiddling with settings to resonate the Victorian era concrete and wondering why in the world he was doing this. It would take weeks, perhaps even months, to find the right resonance frequency, but Rose didn't need to know that. It would only add to her growing sense of his own dislike of a man who he had no business disliking. After all, he didn't know anything more about this Jack Harkness then he was a con artist, a former Time Agent, and he was morally corrupt. After all, why would any of that mean he would think less of the man?

"Why don't you like him?"

"Why do you trust him," he shot back, glaring over his shoulder at her.

That gave her pause. She shrugged, considering for a long moment, halting the rocking of her ancient chair. "I don't know. He hasn't given me much reason not to."

"Very generous of you," he snorted, turning back to the window.

"You just assumed he was bad right off the bat! As if that is any better."

The Doctor resisted the urge to curse, loudly. Really, Rose could be impossibly Pollyanna about the universe when she wanted to be, and it was at times like this he found it insufferable. "He's a Time Agent."

"So?" The words had no meaning to a girl who witnessed time travel with him everyday. He sighed, twitching at buttons on his screwdriver, before explaining.

"The Time Agency is formed in the 49th century by a bunch of humans who figured out how to jump through time. They thought they would have the brilliant idea of trying to make the universe better and stop those who threatened humanity. Noble idea, of course, and like most human, noble ideas, it was flawed."

"Flawed how?"

He paused in his poking around the concrete of the window to turn to her, leaning back against the cold, damp wall. "Humans, even at their most brilliant, and they can be brilliant, can only perceive time one way. Oh, they can conceive of time in different ways, it's why you lot love your time travel stories, and your alternate universe stories, and stories about different dimensions. But time doesn't work in a straight line, nor does it work in strings. It doesn't work from one point to the other. It's more liquid than that, more fine, like a spider's web made water, delicate and gossamer, with zillions of possibilities, more than anyone could imagine."

"Is that how you see it, then? Like this...spider web...thing?"

"No," he cocked his head, trying to explain, and finding that English had no analogies for what time was. "Time is like liquid crystals, like golden, fiery rivers that spill into each other in these weird, Escher like ways. It's just…too hard to explain."

"Why? Because I'm human?" Her eyes flashed in the dim light. Humans were always so touchy about things like this.

"Yes," he shot back with a smirk. "That was the Time Agency's problem too. They were human. They tried, bless them, to make supercomputers that could calculate all possible outcomes. But you see, that's the problem with computers, they are only as good as the people who program them in. And in the end, they only botched the whole thing up and made a mess of it all."

Rose gave him the long suffering look that said she was trying hard not to be offended. "Right, so okay, Time Agency, not the greatest idea in the world, but why does that make Jack a bad guy?"

"Cause he's a Time Agent," the Doctor shrugged simply.

He could see Rose quietly counting to five to herself before continuing. "Yeah, but that doesn't explain to me why he would be bad."

"The idea of the Time Agency is to stop things that threaten humanity. To change history." He nodded at her pointedly. "You and I both know what happens when you do something like that."

Rose swallowed hard, nodding her head silently.

"Yeah, well they never got it through their thick heads," the Doctor muttered darkly. "Their entire idea was to change history without being seen. To leave a mark, but go unnoticed. They liked to pretend they didn't exist."

"Sort of like the Men in Black then?" Rose couldn't even say that term without snickering a little.

"Don't mock, there are men in black, and yeah, that's the idea. Except the Time Agency was idiotically bad at it. They didn't care who they hurt or what they had to do to manipulate things to what they wanted. And they didn't stick around for any of the consequences."

"So, what you are saying is that, based on previous experience with a broad group of people from a few centuries in the future, you can tell that this man you just met is a horrible person, obviously completely untrustworthy, and will do nothing to help us?"

"Pretty much," he nodded, pushing off the wall as he turned back to the window.

"Right," she drawled, returning to the squeaky rolling of the chair. She was silent for a long moment, while he returned to fiddling with settings and poking at the bars.

"Where you all any better at it?"

He frowned, trying to make sense of her sudden non-sequitur. "Who was any better at what?"

"Time Lords," she asked softly. "Where your lot any better at mucking about in time than the Time Agents?"

"Yes," he said, not bothering to look back at her. "We were born to it."

"Mmmm." Rose made no further reply, listening instead to Glenn Miller on the radio, her rubber soles squelching against the tiles.

The Doctor returned to his concrete resonating, which was going nowhere, and promised himself that next time he'd put a leash on her so she wouldn't pick up any other strays.