The Doctor leaned forward as he read the results of the TARDIS' scan. The leftover energy of another dimension had already started to disperse where these things had come through into this world, but so many had come through all at once that there was still enough for the TARDIS to register it.

He could already pick up a few traces of it in other places, but it wasn't consistent, and it seemed to be fading.

"There's a short time window," he explained, turning the screen so that the brothers could see it, since the TARDIS would translate the readouts into English. "The longer they're on Earth, the harder they'll be to track."

"Could be because they're taking the shapes of people here," Sam said thoughtfully. "If you're searching for energy from another dimension, but they've got bodies from here…"

The Doctor pointed at Sam. "Exactly."

"So… you'd have had to show up the second they showed up to catch them?" Dean asked. "Did we miss the window?"

"Well," the Doctor said carefully, "no harm in trying, right?"

"Sure," Dean said, his arms crossed as he leaned against the railing, glaring at nothing—but not quite in the same way that Sam had been glaring at nothing.

The Doctor sighed. "Be right back," he said, temporarily abandoning the main console room to duck deeper into the TARDIS to get the supplies he'd need to make the beginnings of a hare-brained scheme work. If he played his cards right, he could get a scan going and also get the boys somewhere they could take their minds off of things.

Nothing wrong with running from a little bad news, right?

It was perfectly healthy, right?

The Doctor shook his head to himself, tucking his tongue into the corner of his mouth as he searched through Closet Number One Hundred and Seven. "Careful, Doctor, or you'll start talking to yourself," he muttered.

Soon enough, he had his arms full of everything he needed, and he bounded back up to where the Winchesters had their heads together, already coming up with new plans, more likely than not. "Make way!" he declared, since he couldn't quite see over the top of everything he had balanced precariously in his arms.

Quickly, Dean and Sam got out of his way, and he practically dropped everything on the floor in front of the console, setting it all out, letting his glasses drop toward the front of his nose before he pushed them back up again, consumed every bit by the project in front of him, so that he forgot entirely why he had been in such a rush to find somewhere new to travel in the first place.

Some part of him knew, though. Some part of him was too-aware of how easily, how seamlessly, a new project could take his mind off of things. Why else was he always running?

"So," Dean said after the Doctor had well and truly lost himself in his project. "What's up, Doc?"

The Doctor snorted. "Really?"

"It was sitting there, and if no one said it, it was a missed opportunity."

"And you'd never let one of those pass you by."

"Never." Dean leaned back with his arms crossed, waited another few seconds, and then pressed again: "Seriously, what are you doing?"

"Well," the Doctor said, finally sitting back from what he was working on, "I should be able to give you something portable. If these things are puppeting people, a blanket scan might miss them. But I can give you a proximity alert."

Dean looked down at all of the equipment the Doctor had pulled together. "You got anything actually portable?" he asked dryly.

The Doctor laughed. "This isn't the locator," he said. "This is just for information gathering." He got to his feet and put his glasses away. "Now then," he said, "help me set it outside the TARDIS?"

Dean straightened up with a task to do. "Yep, sure," he said, grabbing one end of the device and helping the Doctor carry it, sideways, out the front door.

"Right here is perfect," the Doctor said once they were a few feet in front of the TARDIS. They gently set it down, and the Doctor crouched to punch in a few numbers. The machine whirred and blinked, then set to work, leaving the Doctor perfectly pleased with himself.

"So," Sam said, "are we supposed to be impressed now or…?"

The Doctor sighed and shook his head. "It's taking the dimensional temperature," he explained. "Well, that's not quite it. Well, that's the best explanation. Well, it's more of a barometer than a thermometer—"

"And when it's done, it will be… smaller?" Dean asked, wrinkling his nose.

"When it's done, that hatch will open, and out pops your own little screwdriver!" the Doctor explained happily.

Sam and Dean turned fully toward each other, eyebrows raised. "A sonic screwdriver?" Sam asked.

"Well," the Doctor said, "not sonic."

"But still helpful," Dean surmised.

The Doctor touched the side of his nose and pointed at Dean. "It'll tell you when something that shouldn't be in this reality is around."

"Like you?" Sam asked.

"I'm from here, thanks," the Doctor said, though when Dean snorted under his breath, he decided not to press it.

"Okay, so," Dean said slowly, "how long will this take?"

The Doctor nodded toward him. "Needs about twenty-four hours to calibrate." He waited for the boys to nod their understanding and then, with half a smile, said, "In the meantime, what do you say to a quick trip?" He held both hands out in front of himself. "I'd take you right back where I left you."

"Yeah," Dean said, so suddenly and forcefully that it got both the Doctor and Sam to turn sharply toward him. He cleared his throat, a muscle twitching in his jaw. "Yeah," he said again. "Sounds good."

Sam shared a look with Dean that carried an entire conversation, but when it was over, he nodded, slowly and carefully. "What did you have in mind?"