It started on an overcast day in late nineteenth century Scotland.
It got worse from there.
"I dare you."
Rose gave him an intrigued look from behind her fan. "Seriously?"
"When am I anything but serious?"
She snorted softly. Not quite softly enough, apparently – an older woman in a particularly ridiculous wig glared at her. "She does realise her hair is shaped like a goose, doesn't she?" Rose whispered, leaning into him.
He chuckled and returned the pressure of her warm arm against his. "It's a swan," he said into his drink. "Very fashionable at the moment."
"And I thought mine was bad," she muttered, her hand going self-consciously to the pile of white curls pinned painfully to her poor scalp. "You were saying?"
He pulled her hand into the crook of his arm and led her in a slow stroll around the ballroom, hugging the wall. "Ten quid if you can get her to say it."
She pursed her lips. "I don't know. Isn't it a bit…"
"Petty? Morbid? A massive abuse of the most basic tenets of time travel?"
"I was going to say 'mean', but those will do." She glanced across the room at the girl in question. She was laughing loudly, the sound false and slightly grating. "She's so young," Rose said quietly.
"There's nothing we can do," the Doctor replied, now regretting the suggestion.
"I know." She straightened and released his arm. "Be back in a mo'." Rose moved across the crowded room, still a little awkward in unfamiliar shoes and bulky skirts, to join the gaggle of courtiers surrounding the girl. "I beg your pardon, Your Majesty," Rose Tyler said to Marie Antoinette, Queen of France. "I wondered if you had anything in particular to say about the cake served this evening? And who, maybe, might want to eat it?"
Rose shook her head vehemently and leaned back against the warm stone wall. Stragglers from the parade wandered past them. "Did you see the size of that sword? Because I did." She frowned. "What're you supposed to call him, anyway? What's his title? 'Cause he can't be a 'caesar'. That'd just be silly."
"Proconsul. No, consul." The Doctor's brow furrowed. "No, wait. 47 BC – just 'General' will do, I think." He scratched the back of his neck with one hand. After a moment he said, "I didn't think his sword was that big." Rose grinned.
"The one you used in the fight with the Sycorax leader was bigger."
"Well, maybe," he said coolly, but couldn't control the smug twitch of his lips. "Not that it matters to me, of course."
"Of course," she replied, ducking her head to hide her smile.
"I knew it. You're chicken."
She scowled. "You," she said, poking him in the side, "are just disappointed we haven't run into any trouble yet and hope I'll start some."
"Well," he replied, poking her back, "you do have a talent for it." He paused, scuffing the toe of his trainer in the dirt. "It's okay if you're chicken. I won't think less of you."
She sighed and let her head fall back against the wall of the Senate building. "You're impossible."
The Doctor began to cluck softly under his breath. A few passersby sent worried, furtive glances in his direction. Rose gripped his elbow and squeezed hard. "Doctor, you're scaring the locals."
The clucking grew louder. She knew it was only a matter of time before the bawking began.
"Fine!" she hissed and he shut up abruptly, beaming at her. "You said he'll need to come 'round this corner to get to the Senate?"
He rubbed his hands together eagerly. "Any moment now. They've requested an account of his triumph over Pharnaces the Second at the Battle of Zela. Today he utters those immortal and impressively succinct words, 'I came, I saw, I—'"
At that moment, an imposing man with a hawkish face and very large sword strode past them. Rose turned to the Doctor. "Twenty-five quid."
He grinned. "Done."
Throwing caution and what little good sense she had left to the wind, Rose ran after the man. "Excuse me, General Caesar?" She gave him her most blatantly flirtatious smile. "If you had to describe your latest visit to the country in only three words, what would they be?"
"This," the Doctor said to himself, "is getting out of hand."
This was putting things rather mildly.
He clutched his unlit torch and crouched low to the ground when one of the search lights dipped too close to his hiding spot by the towering wrought iron fence. Hidden in the shadows, he gritted his teeth. "One more minute, Rose," he whispered. "Bet or no bet, one more minute and I'm coming in there after you."
Then the quiet country night was disturbed by the unmistakable sharp barking of guard dogs. The Doctor had nearly reached the top of the fence when he heard a soft giggle from above. He looked up to see Rose clinging to a tree branch overhead, her eyes bright and her grin impossibly wide.
"You are a lunatic," he called up to her softly, and dropped to the ground. The barking grew louder. She slid from one branch to another, and soon, with a little help, slipped from the tree trunk to the Doctor's arms. Her knees were a bit wobbly but a quick glance at her face told him she was shaking more from laughter than from fright. "An absolute lunatic," he said again, and couldn't help but press his lips to her forehead in a quick, fierce kiss.
She wrapped her arms around his neck. "I may be a lunatic," she said giddily, "but I'm a lunatic who just mooned Winston Churchill." She grinned. "You owe me fifty quid."
They heard shouts and pounding footsteps approaching from the garden on the other side of the Chartwell House fence.
She slipped her hand into his. "Time to run?"
He gripped her fingers. "Oh, I should think so."
And they ran into darkness, laughing.