"Hold on, I forgot something," said Rose as she went back into the TARDIS. The Doctor huffed, pretending to be highly exasperated. Humans were so high-maintenance.
Just then, some one who certainly looked like Rose came running out of the trees towards him and the TARDIS, which he had coincidentally just seen her enter.
"Rose, how did you…" the Doctor trailed off, very confused.
"Oh thank God! Doctor! I was so scared you wouldn't be here," Rose panted, as she threw her arms around him. He half-reciprocated, still trying to figure out what in the blazes was going on.
"Rose, how did you… What are you… Wait," he glanced down for the first time noticing the rather see-through gowny type thing she was wearing. "What have you got on?" he stammered, rather distracted from the more pressing issue at hand.
"Does it really matter?" she asked, looking up at him. "We're both alive. I was terrified that you'd…" she shuddered slightly before leaning up to kiss him rather desperately. Which he was more than happy to return, until he managed to clear his head and remember that something was very, very wrong.
When he abruptly broke the kiss she looked slightly hurt, "Rose, you just walked into the TARDIS less than a minute ago…" but she wasn't really listening, she was looking at his chest like it held some kind of anomaly.
"Doctor, when did you change your tie?" she sounded like she was trying to puzzle something out.
"Pardon?" the Doctor was growing more confused by the second.
"This morning, before we got separated, you were wearing that awful paisley one you insist on keeping. When did you change it?"
"Rose, you 'accidentally' ruined that one in the wash years ago. It was rather upsetting. Don't you remember?" he asked. He was concerned, because that had been quite the ordeal for her to forget. Then it hit him. "Oh, hell."
Rose seemed to realize at the same time because a small "oh," escaped her lips.
"Oh my god." The Doctor spun around. There was another, more decently clad, Rose Tyler standing in the doorway of the TARDIS quite as much in shock as he was. Yes, this was very, very bad.
After several moments of shocked silence the apparently slightly younger Rose spoke up. "Somebody better know what the hell is going on!"
Slightly-Older-Rose giggled a little in response. When the other two rounded on her with rather angry glares she elaborated. "I do," she gave a little self-satisfied smirk before turning to the Doctor. "I think you just cheated on me. With me."
"Yes, thank you," the Doctor cleared his throat, being made more than slightly uncomfortable by the situation at hand. "But what is going on exactly?"
She snickered again. "Doctor, do you remember our trip to Trivolka that didn't go quite as planned?"
"Of course. We got separated and the when we got out you were wearing something very…like that, actually," he said pointing over his shoulder at Younger-Rose. "And you were acting funny, you kept giggling and wouldn't tell me what happened, I wanted to test you for foreign chemicals, but you insisted you were fine," and then it dawned on him. "Two weeks later, you 'accidentally' ruined my favourite tie on purpose."
Older-Rose nodded. But Younger-Rose still looked more than confused.
The Doctor continued, "But we're not on Trivolka, were not even in the right year. None of this makes sense."
Younger-Rose spoke up, finally understanding, "Doctor, I've always wondered about your piloting skills, they've always been a little… questionable."
"Oi!" he began defensively. But Younger-Rose cut him off.
"Anyway, if I'm to understand this correctly, you're my future," she said pointing to Older-Rose, "and so are you," she said, pointing to the Doctor, "and my Doctor is somewhere unknown," she finished, an edge of worry creeping into her voice.
"He's fine," Older-Rose, said comfortingly. "He's not half a mile from here, in that direction," she said pointing northward. "You should go find him before he gets into more trouble."
"Yeah, I should," she said, turning to leave, mind whirring with this encounter. "Years ago," he'd said about the tie. That meant she still had years with him. She smiled to herself.
"And remember," Older-Rose yelled after her, "if you don't wreck that tie next time you do the wash it will create a paradox," she sounded just a little too happy.
The Doctor shook his head, watching his past walk away. "Leave it to you to hinge two-thirds of the universe on the destruction of my favourite tie," he said, turning to his Rose.
"Yes, well, I think you'll find it was your idea," she replied, before sauntering off into the TARDIS.
"Wait a minute," he said, following her in, "this means you cheated on me, with me, as well. And you kept it from me."