"Oh no, no, no. Definitely not. No, he's not at all like a vampire. Much mo-"

That was the first time the doctor winked out. It was so brief that Amy almost missed it. He was in the middle of a sentence and he just...flickered, like a bad television signal. He was there, and then he wasn't. Then immediately he was there again.

"-ore blue, with tentacles-" and then he stopped.

Slowly, he put his hand to his head, as if he was in pain. He turned to look at Amy, a puzzled look.

"Did I just...? ...Did ...you just...?"

"Doctor, you...are you ok? It looked like you...disappeared for a moment. I think. Did you see it, Rory?"

Rory looked up from his task on the other side of the TARDIS console. "What? Did I miss something?"

The doctor waved his hands dismissively, "No, no, no, definitely nothing. I think. No, I'm sure of it."

He paused again and his hand returned to his temple. He seemed to look inward. "Blasted headache, though."

Amy was still standing on the other side of the console; now she moved closer. She felt Rory step up behind her. "It wasn't nothing, Doctor; I saw it. You...flickered. Like you went somewhere. Or...like you...you're..." she paused, thinking. "You're not a hologram, are you?" And she pushed at him, half-joking, and also half-seriously. But his jacket was its same solid tweedy self under her palm, and his shoulder was firm and warm below that. He smiled at her.

"Back off, Pond. I'm as real as an Ood. But...hm...flickered...now that's tricky..." He looked around, losing himself in thought, half-smiling. "I would like to know what..." His voice trailed off as he held up the sonic screwdriver and took a reading from the air.

"Interesting...I wonder what that-"

And like a switch had been tripped, he vanished.

Amy and Rory sputtered. "Doctor? Doctor! DOCTOR!" They spun around, looking all over the central room of the TARDIS. He did not reappear.

Amy turned accusingly to Rory. "What did you do?"

"Me? You're loony. I was just standing here with you. What did HE do? That's the question!"

Amy turned back to look at the spot where the Doctor had been. "You're right, you're right, I'm sorry. You're right. DOCTOR!" She yelled again, uselessly. She skittered over and knelt where he had been standing. She peered at the floor, then looked up, staring at the console where his right hand has been resting.

No secrets were revealed. The Doctor did not reappear.

She felt a sudden yank on her shoulder as Rory pulled her away from her crouch. "Ow! Rory!"

"Don't stand there! What if he just...comes back? You could be...I dunno, squished or something..."

"Oh." She hadn't thought of that. "yeah. Well, what do we do?"

Rory looked a little paler. "Well he'd better be back, yeah? I don't know how to fly this thing, d'you? I don't even know where we are!"

Amy's nose wrinkled in thought and worry. "No, me neither. Let's find out. Maybe we can get help." Ignoring the alarmed look on Rory's face, she pushed past him and ran to the door.

"No! Amy! Wait! Don't open it! Who knows where we are!"

"Exactly," said Amy, with satisfaction. She grabbed the door and flung it open - and stumbled immediately backwards from the blinding light that violently poured over her. It was like a blow, forcing her back into the room. It burned through her eyelids, heating her skin. She couldn't see outside the TARDIS at all. It was as though they were in the middle of the sun.

"Ow! Shut the door!" She dimly heard Rory run up to her, and together they pushed the door shut. They leaned against it, gasping. Slowly they sank to the floor.

"Well, that's a dead end," said Amy drily.

"Where the hell are we?" sputtered Rory.

Amy ignored the question. "Can't fly it, can't leave it, don't even know how to use the toaster oven..." She paused, thinking. Then: "Ooh, the phone!"

She jumped up and ran back over to the console, and grabbed the old handset. "Hello?" she shouted into the plastic. "Is anybody there?"

There was no one on the other end. She glared at the typewriter and the vacuum tubes in front of her, frustrated; stood on her tippytoes, craning her neck to look above her, looking for any instructions on Who To Call In Case of Flickering Timelord.

Nothing appeared.

"Rory, have you ever seen him dial this thing? Hello?" she said again, as if something had changed. It hadn't. The phone was useless.

With a frustrated sigh, she dropped the handset back into its cradle. She looked at Rory, feeling petulant. "Well," she said, feigning certainty, "he'll be back."

Rory was not hiding his panic well. "He better be, or we're screwed!"

Amy sputtered and tried to deny it, and then caved. "...Yeah...but we won't be. He'll come back. He will."

Wisely, Rory bit his tongue. Because he couldn't think of anything else to do, he silently offered Amy his hand. They sat down on a step. Amy curled up in Rory's arm. He hugged her tight. Both of them stared at the spot where the doctor had disappeared.

Neither of them spoke the thought out loud: What if he never returns?