Disclaimer: I don't own Doctor Who.
The Doctor philosophised in a folding chair. Originally, he had suspected some wires of mischief and sat down to keep an eye (perhaps two) on them, but they behaved. Then he had looked up at the soles of his companions' boots, which, as they were just standing next to the console, was equally terribly uninteresting.
The TARDIS noises were normal and soothing.
He shut his eyes for a moment.
"Doctor!" shouted Amy, a bit listlessly. "A tube-thing just came out of the ceiling! Aaand now it spat out a paper plane!"
"Plane flew into the console!" reported Rory.
"Now there's a fire!"
The Doctor opened his eyes and hurried upstairs as dignifiedly as possible, to find that Rory had retrieved the plane and Amy wielded the fire extinguisher with grace.
He bit back a cough, graciously accepted the plane from Rory and unfolded it; the paper was only a little charred. "It's an ad! A sale. A shopping centre on ABC dash seven. 'Quality hats on floor nine'. I could use a hat, but this is going too far!"
"You get post through a tube?" asked Amy, extinguishing one last flame.
"Not usually, I admit, but the TARDIS has re- Oh!" He flinch-laughed as if someone had tickled him. Hauled out the psychic paper. Frowned at the message. "'A surprise on floor 228.'"
"The same shopping centre?" asked Rory.
"Probably," said the Doctor, and started programming the TARDIS. The smoke had almost cleared. "At least I know who it's from."
"Who?" asked Amy, looking decidedly expectant.
"Recognised the handwriting."
"Floor Hats or Floor Surprise first?"
Amy hefted the extinguisher. "Who or I'll use this!"
The Doctor shrugged and willed one of the criss-crossing thought processes he had going on to lead to some words that made sense or else somehow garner his companions' attention – and then a part of the TARDIS that usually didn't explode that often obliged.
The TARDIS materialised on the ground floor of the shopping centre; to preserve the aspect of the surprise, or so the Doctor said. That floor was decidedly boring-looking, and full of nothing but lifts and people.
"Onwards!" said the Doctor, following a crowd of beings into the closest available lift.
The lift whined with the efficiency of the 58th century, and that's really all that could be said about it. The Doctor conducted a quick survey and found that no one else was going to floor 228. Apparently floor 228 wasn't very popular. Apparently people made faces at the mere mention of it.
It was, however, a library. Or a bookshop. Of some sort.
There were stacks of books all along the corridor the lift let him, Amy, and Rory out into. There were also stacks of various (most likely) fruit preserve and empty picture frames.
"I wonder if the surprise is a good book," mused the Doctor, looking around. The corridor branched out into rooms; every door was perpetually open. The books and jars and frames were perpetually everywhere. "I'd like that, but it's probably not. We don't see eye to eye on genres, do we."
"Who?" growled Amy, stomping her foot.
"Let's peek, shall we. Spread out! Peek! Look for anything and everything! It's like a giant maze of fun!"
It was Rory who found the surprise.
Then he tried to find the Doctor but got a bit lost. Then Amy found him. Then they joined forces and finally located the Doctor.
"There's a woman here," said Rory, quietly. "A woman, us, and ten thousand jars of unappetising… future stuff."
The Doctor looked up from the mouldy spot of wall he'd thought looked promisingly surprising. "A woman?"
"Yeah. Reading. Obviously."
"In there," said Rory.
The Doctor strode confidently into the room. And then he stopped. And then he swallowed. Then he said, "I really should have peered around the corner first."
It was a large, cosy room. The walls were (unsurprisingly) covered with bookshelves, and a passable likeness of a fire whispered in a decent-looking fireplace. There was indeed a woman in there. She sat in an armchair and read a book with a silvery cover. She didn't look up once, even though she faced them and reached up to push a blonde strand of hair behind an ear three times.
"Something's wrong, yeah?" whispered Amy.
"No, no…" said the Doctor.
"On a scale of one to hide-in-the-TARDIS, how wrong is it?"
The Doctor shook his head. "She shouldn't be here. She's supposed to… She can't have… Unless she's somehow… and chosen the same body a second time. You haven't, Romana, have you? Have you? Have you? No, she can't have..."
"You know her! Ooh, Doctor, you charmer. Have you soniced her too?"
"Amy!" he hissed, giving her his best withering stare.
"So… you know her?" asked Rory.
"She shouldn't be here."
Amy put a hand on his shoulder.
After a moment, Rory placed a hand on the other shoulder. "Sometimes impossible things happen and we call them miracles?" he offered, looking a little puzzled.
The Doctor gave a raw chuckle.
"Aren't you going to introduce your friends, Doctor?" called Romana, flipping a page.
He read her face and skimmed her mind, and she quirked her lips and genuinely didn't understand his concern. He sighed in relief, bit his lip. "Amy, Rory – the Ponds – Romana."
Amy and Rory grinned and offered their hands.
Romana smiled winsomely and shook them.
"I take it I have later incarnations."
"Well, yes. Yes." The Doctor grasped her shoulders gingerly and then let go again.
"Well, can't be helped." Romana reached for his arm and linked it with hers.
"How long have you been here?"
"Oh, long enough. I've raised a fair amount of dust bunnies."
"How did you get here?"
"Met a Face in a bar. He gave me this." She handed him a table napkin with the address and the words 'A Doctor on floor 228'.
"Did you really lose a hand in a swordfight?"
The Doctor sighed. "Yes."
Romana looked back at the tome she'd left on the chair seat; wrinkled her nose at it. "Let's get out of here. This place is illogical: fully automated and there isn't even a checkout. No one ever comes; it's dreadfully boring. You know, I've come up with three hundred and fifty two things one could do with books, preserve, and picture frames, and not a single one is very nice in practice."
"Explains why you're on this floor." The Doctor nudged a jar containing something bright red with a toe. "Why this building?"
"Used to be Torchwood, apparently, before it was sold. He probably kept a key."
"So, can we drop you off somewhere? Anyplace you feel you should go?"
Romana shrugged one shoulder. "I'm not sure I can get very far. Are you going to be attached to my elbow for the rest of the foreseeable future?"
"Yes," said the Doctor. "As you've no doubt foreseen."
Amy and Rory exchanged looks. "When are you two performing next?" asked Amy.
The Doctor ignored that. "I wonder if floor nine's open. I'd like to try on some hats."
"Oh, has the sale started?" asked Romana.
"There's a sale there," he informed her.
"Oh, how interesting!" Romana placed her hands on her head and spent a moment looking deep in thought. Then she nodded. "We're going!"
"So… nothing more important to discuss than hats, then?" wondered Amy, as the lift whined downwards.
The Doctor tsk-ed, absentmindedly patting Romana's arm. "Hats are important. You wouldn't believe the number of hats that get lost."
Romana nodded. "Yes, it's quite a problem, really."
"Of course, I myself have never lost one, but..."
"Yes, you have. Shall I list them?"