The Doctor whirled his way around the console, letting his coat flare a bit as he spun. Coat flaring was cool, he decided. What was decidedly not cool, however, was that new annoying itch at the back of his mind.

He must have forgotten something. Yes, that was definitely it.

He'd had a faint irritation there for a while now, but it wasn't enough to really bother him. But suddenly it had become quite insistent. Very strange.

Actually, wait, no. It wasn't strange. It was... Somehow he knew this itchy feeling but he couldn't quite remember what it was. Perhaps once he remembered it would go away. That must be it.

He heard footsteps coming down the hall. The TARDIS brightened the lights near the corridor entrance.

"I see you're finally warming to Clara!" the Doctor said approvingly, running his hand along the console. The TARDIS made a faint snorting sound, as though she were rolling her non-existent eyes. Stranger still.

Not strange - mysterious! Yes! Just a lovely mystery to solve! Perhaps he could even wear his Sherlock Holmes hat again.

"Clara!" the Doctor exclaimed without turning around. That itch was really getting quite annoying. Was it an infection? Some sort of mind mosquito perhaps?

"Doctor, there's -"

"Have you ever felt like you were forgetting something vastly important?" the Doctor cut Clara off. "And have you seen my Sherlock Holmes hat?"

"Well, I'm glad to see we're still rude at least." The Doctor froze, his hand hovering over a switch. No, he must be having hallucinations now. Perhaps he wasn't even in the TARDIS. Maybe he was back in... whatever planet it was he last got arrested on. To be honest, the jails all kind of blurred together after a while - apparently the condition and decor of prisons was perhaps the one constant across the universe.

He wondered what that said about the state of said universe.

"Doctor?" Clara ventured hesitantly.

"Oh, now he's ignoring me. I never ignored people! Well, when I say ignored, I may have disregarded insignificant things a bit. Well, when I say a bit, I mean... But, honestly, it never harmed things at all! ...well, except maybe that thing about the bees with Donna... really should have paid attention to that one..."

"It's you!" the Doctor suddenly shouted. "You're the itch!" He whirled around and let his coat swish cooly around him.

The thing that shocked the Doctor the most was that he was old.

Old wasn't really the right word to describe his former right hand, but it was just shocking to see the face he used to wear aged. He noticed how the laugh lines had deepened around the eyes. How the formerly clean shaven face was now covered with rough stubble. How the other man was just slim rather than a skinny streak of nothing now.

He noticed the simple gold band around the left ring finger. And his hearts ached, not sure whether to be thrilled with joy or heartbroken.

"Oi, you gonna stand there and stare all day?" his former hand asked, raising an eyebrow. He was one angle of the head away from a perfect Donna Noble impersonation.

"No! Of course not! Sorry, I'm just... You're old. Ah, not that. That just came blurting out, didn't it." The Doctor abruptly shut his mouth, telling his brain to get ahold of itself so that he could properly communicate without making a complete ass of himself.

"Well, it's been a while," his hand replied. "Human aging, single heart, me." The man sighed.

"Now, I could go all storming in and demanding, but there's really no need."

"What?"

"And I'm not even going to ask how or why you did this, but just let me get Rose and we'll go home, ok?"

"Rose? I haven't... you lost Rose?!" the Doctor looked at the other man sharply.

"I didn't lose anyone!" his hand exclaimed defensively. "She has a thing for magnificent sentient ships that travel in space and time!"

"What?"

"Seriously, I just don't have time for the banter," his hand sighed, glancing down at his watch. "Ten more minutes tops, and that's pushing it."

"What?" the Doctor was incredibly confused.

"So just call Rose back from wherever she's wandered to and we'll go home."

"You - you - what?!"

"Oh, am I still doing that what? what? what?! thing?" his hand grinned, bouncing on his feet a little. "I always kind of liked that. Very simple, but dramatic."

"You barge into my console room and ask where Rose is and - How did you even get here?!" The Doctor whipped out the sonic and started scanning his former hand. Said hand's face fell immediately.

"Rose isn't here."

"No." The two stared at one another in heavy silence.

"...Rose isn't here!" His former hand turned and sprinted away from them, back down the hallway. "No no no no no no!" he yelled, skidding to a stop in front of the door he'd come through.

The door was flickering in and out of existence as the TARDIS struggled to hold onto the connection. No, he had to get back! He couldn't get stuck here!

"Come on old girl, try to hold it," he murmured as he grabbed the doorknob and pulled.

When the Doctor and the increasingly confused Clara caught up to him, he was standing in the middle of the corridor holding a doorknob and staring hopelessly at a wall.