Sam was glad to see the Doctor, though he wasn't sure how much good the guy was going to do. There was a time when he'd hoped that the Doctor could help them, but that had been before Hell. Before everything that came after Hell.

He knew, too, that Dean had wanted to ask the Doctor for help and gotten nowhere. So he wasn't holding out hope for any help longer-lasting than whatever their next adventure was. And then, he would get back in his box and leave, and they'd go back to running from Leviathans as add this to their growing list of adventures with their alien friend.

Still, he'd take the help he could get, and he sat down with the Doctor, taking over what was essentially a debrief so Dean wouldn't have to. They were both still reeling, but there was something in the way Dean had taken Cas's betrayal to heart that made Sam wary of making him retell it.

Finally, the Doctor leaned back, looking far more pensive than he usually did, his fingers tented by his mouth. "Well," he said at last, drawing that word out the way that particular incarnation of the Doctor tended to do, "sounds to me like we should pay your new friends a visit."

"We'd have to find them first," Dean said dryly.

"Then let's do that. There has to be a way," the Doctor reasoned. "They came here from somewhere else; they should have an energy we could track."

Sam and Dean shared a look, and Sam smirked to himself as he watched Dean lean forward and ask, "Think the TARDIS could pick up an energy signature like that?"

"Any excuse to drive the alien spaceship again," Sam muttered under his breath, but the Doctor was already nodding along.

"Might be why she brought me here," the Doctor said. "If the TARDIS picked up on something being brought from another dimension—"

"Purgatory."

"—then she might have been drawn to it," the Doctor finished, ignoring Dean for the moment.

Dean glanced toward Sam, and when Sam saw the look on his brother's face, how was he supposed to say anything but "It's worth a shot"? They were both still reeling, still trying to come to grips with the last few days, and the chance to get excited about anything was actually, genuinely, going to do more good than not even if it didn't work.

So, back downstairs they went, and Sam shook his head as he watched Dean grin crookedly at the TARDIS. "You're coming onto a wooden box; you know that, right?" he muttered to Dean.

"She's an alien spaceship, and she likes me," Dean defended himself—which really didn't help his case, in Sam's eyes. "Don't you?" Dean called out to the TARDIS.

It dinged in response, and Dean seemed to take that to mean it agreed.

Sam shook his head as he walked into the TARDIS, glancing around at the interior. He hadn't been inside as many times as Dean had, but it was nice to see that it looked somewhat familiar, anyway. This was the layout that reminded him of being a kid; he liked it better.

He sat down on the overlook, watching as the Doctor moved around the console, talking in jargon that he didn't understand. He watched Dean smile and pat the console encouraging, even if he knew Dean was just as lost when it came to the jargon as he was.

And then, he saw something, just out of the corner of his vision. And his heart stopped.

He whipped his head around, holding his breath … but no, he didn't see anything. Didn't see anyone. He just saw the reflection of light bouncing off of the central column of the TARDIS and playing against the far wall. He must have seen that, not…

Well, if he'd seen Lucifer, then their problems were only going to get worse, weren't they?

But then, he had known the Doctor most of his life. And he knew how protective the TARDIS could be. She wouldn't let anyone in that could threaten them. She had defenses for this kind of thing.

Defenses against the devil himself, though?

Sam swallowed and turned his attention back to what the Doctor was doing. He couldn't be sure he had seen what he thought he saw, and he was, frankly, a little on edge. Not to mention sleep-deprived. Maybe he just needed to lay his head down somewhere safe for a while and he'd stop seeing threats in the corners of his vision.

Yeah, he could experiment with optimism for just a little bit.

"There we go," the Doctor said as he finished whatever he'd been working on and yanked over what looked like a television screen, glancing up at Sam and then readjusting the screen so that Sam could see it from where he was. He grinned crookedly and rapped one knuckle against the screen. "Give her a few minutes, and this old girl should be able to track down your anomalies."

"Great. Now we just have to figure out how to kill them," Dean said dryly.

"Or figure out how to send them back," the Doctor said, tapping his fingers against the inside of his elbow before bursting into another rush of movement around the console.

"You gonna share with the rest of the class, Doc, or do we just get to watch you run in circles?" Dean asked when the Doctor had gone from explaining himself grandiosely to muttering under his breath while he worked.

The Doctor glanced up at Dean and smiled. "Well, it shouldn't be a problem for the TARDIS to track down these little visitors, but sending them back where they came?" He shook his head. "We travel in time and space, not dimensions. Going to be tricky, and I don't want the old girl getting seasick."

Dean nodded, looking thoughtful. "What about Torchwood?"

The Doctor frowned deeply enough that Sam could see an entire history there. "What about Torchwood?" he asked.

"Well, they might be tracking something like this. Jack reached out to me the last time, and I think they're smart enough to figure out something's off," Dean reasoned.

The Doctor was quiet for longer than Sam thought was necessary before, finally, he smiled and went back to what he was doing, fiddling with the console and adjusting a few different levers. "Let's start with finding them, shall we?" he said, breezing right past the suggestion, his voice a little too bright.

The Winchesters, Sam realized, were a distraction for the Doctor. Something else was going on. And at that point, Sam was all but bracing himself waiting for the fallout of it.

Everything else had blown up in their faces so far; why wouldn't this?