A/N To answer a question, I see this as being after the Ponds and before Clara. It can be considered a somewhat alternate timeline for the Doctor, since he didn't necessarily pick them back up again- in other words, the Ponds could have gotten their happily ever after at the end of season six, with the previous fic tacked onto it but without their later season seven episodes. I made it generally unclear, though, so it's up to interpretation.

Thanks to theblonde2243, Byrneshadow, mudkipz, glaringowl, and .3

Disclaimer I don't own Sherlock/Doctor Who/Supernatural/the Avengers/Jekyll, or any associated characters, events, etc.


CHAPTER IV. Tower

Rose Tyler. To Castiel, the name was entirely unfamiliar, and none of the others seemed to recognize it, either. Odd, considering how proud Director Fury looked to announce it, but rather than questioning anything, the angel remained silent, watching intently and taking in everything that was spoken, in hope of understanding better.

"Rose Tyler," Sherlock repeated, his eyes narrowing swiftly. Judging by the tension in his neck and shoulders, he could tell something about her was unusual, and, when he focused, Cas could as well—she wasn't inhuman, but there was something equally haunting about the young blonde woman. Despite undoubtedly originating from Earth, there was still an air to her that seemed… otherworldly.

"Sherlock Holmes?" she replied, chin dipping in a nod. "I've heard… quite a bit about you."

"Have you?" Sherlock's eyes flickered to Fury, but both he and Rose shook their heads.

"Not from him," she clarified. "There was a book, back where I come from. Well—several books. You're, well…"

Castiel's eyes narrowed as he focused more intently on her. There was excitement in her tone, carried underneath the overwhelming air of casual coolness that she was clearly trying so hard to project. Something about her seemed younger than the way she looked physically, bubbly and eager, and yet simultaneously dark and mature. This Rose Tyler, whoever she was, certainly seemed to be quite the intriguing person, and for reasons that even an angel couldn't quite target.

"…You're a bit fictional," she finished, a real smile curving her full lips. An expression of utter and complete confusion passed over Sherlock's face—Dean, next to Cas, snickered lowly, and Cas figured that the hunter was greatly savoring the baffled expression and how it looked on the usually arrogant features of the detective.

"Fictional?" Sherlock repeated, the word carefully formed, each syllable painstakingly articulated.

"Rose is from an alternate reality," Fury spoke up, but was almost immediately cut off by Rose, who seemed remarkably at home next to the generally intimidating director. And he allowed her to speak, too—there was an interesting sort of mutual respect that balanced delicately between the two of them.

"I haven't always been. I traveled with the Doctor a few years ago, then there was an… incident, and I ended up on the other side of reality. I managed to make my way back once before, only to return just a bit later. But then…" She cast her eyes down, and Cas stiffened suddenly—there was something in her pupils, which was only briefly visible as she lowered them—a bright yellow glow, flaring swiftly before receding back into darkness. Cas zeroed in on her even more intently, and the strangeness that he'd sensed before reared up momentarily. This truly was like nothing he'd ever encountered—not angelic power, or demonic, or anything in-between. It was as if Rose Tyler had access to the very fabric of the world God created—as though she taken the needle right from His hands and began creating her own stitches.

"Let's just say that reality doesn't serve as much of a barrier to me anymore," she murmured.

Nobody had a response to that, and Fury immediately launched back into speech before the silence could stretch on long enough to become eerie. "Neither do time and space, so finding the Doctor, for Ms. Tyler, won't be a bit of a problem."

"Not at all," Rose confirmed, straightening up again. She looked younger again, that childish excitement leaping back into her gaze, and Cas remembered what she had said, about being separated from the Doctor. Was there another Doctor in the reality Rose had been living in, or was she entirely alone there, condemned to a strictly human lifestyle? Of course, she hardly seemed human as it was, even without an extraterrestrial partner. Though surely she hadn't always been that way.

There were a thousand things about her that were hauntingly mysterious, and when Cas attempted to search for answers, gently brushing out against the edge of her consciousness for a light mind-read, he found only a blazing energy that was shocking enough to cause his retreat. He managed to keep his vessel's expression in careful neutrality, even as an internal shudder passed through him. The charge surrounding her was vivid gold and burned at the temperature of the sun—not only was this woman an enigma, she was also a threat, a very distinct and immediate threat that was easily enough disguised under the skin of a strong but generally benign-looking person.

"Alright, then, what are you waiting for?" Tony questioned, leaning forward and looking more than a little interested. "Vortex energy, right? Let's see it."

"It's not really a visible thing," she explained almost nervously, but Fury nodded behind her.

"No need to waste time. Go on now, agent, we might as well get him here as quickly as possible."

She swallowed but nodded, then dipped her head down for a moment, eyelids settling shut. For an instant, the whole room seemed to hold its breath, and a rustle of leather came from the side as Dean adjusted his position, watching with wide eyes. Four long seconds passed, then Rose's head jerked up so suddenly that it looked momentarily as though she'd been possessed—enough so, in any case, that Cas tensed instinctively, and felt Dean do the same beside him.

When her eyes opened, though, they were the color of no demon Cas had ever seen or imagined. The closest he could associate them with were those of Azazel, the scapegoat of hell, but while the high-ranking demon's had been a vibrant yellow, these were pure gold—glittering, and almost blinding, casting an ethereal corona that bathed her features in light. Several occupants of the room gasped, and Thor took a step backwards, while Sherlock's eyes widened in almost delighted amazement and Bruce's jaw fell open slightly. Fury looked rather pleased, but also a bit wary as Rose's lips began to move, her voice pouring out. She sounded different, too—her words rang, almost echoed through the suddenly small-feeling space.

"Doctor," she breathed. Though she only spoke it in a whisper, it was loud in the way that it coasted to every corner, breathy and windy, like the words of an air sprite. Then, all at once, her expression was consumed by a wide grin that illuminated her features even more effectively than the glittering light. She raised a hand, slowly, and jerked it to the side. In perfect sync, the door flung itself open, and standing there was the familiar figure of the Doctor, looking utterly shocked and with his hair sticking straight out as though electrified. By the time Cas glanced back towards Rose, she had relaxed her shoulders and let her arm drop, and her eyes were their normal dark brown again—she looked as human as she ever had.

"Now, that was a bit odd," the Doctor decided aloud, running a hand through his hair and looking around in almost delighted confusion. "Oh, it's you lot again, is it? Of course it would be, nobody else is quite so fond of interrupting me during very important—"

His voice stopped immediately, as if it had run into a brick wall—no, more like it had dropped off a cliff, because there was no noise of surprise, no impact. He simply went silent, as if all of his words had been sucked out of his lungs, leaving him literally speechless. His jaw was still open, in the middle of forming a syllable, and his eyes were wide—unblinking as he stared across the room, suddenly not seeing the rest of them, not seeing Cas or Dean or Tony or Steve or Sherlock or John, not seeing anyone who wasn't Rose.

His lips formed her name—Rose—but still no sound came out. And she stared back with equal disbelief, moisture swelling in her eyes, her breath audible.

Perhaps five seconds passed this way, and then they both gave at once, half-running and half-stumbling across the room before crashing into each other all at once, arms tight around the other. He laughed, more loudly and genuinely than Cas had ever heard before, and actually lifted her off her feet, spun her through the air in amazement.

"How—?" he began, but she cut across him with a simple shake of her head, shoulders trembling with pure joy.

"Doesn't matter," she insisted. "You—you look different."

As caught up in the emotional reunion as the rest of the room seemed to be—even Dean had a serene sort of smile in place—Cas was rather intrigued by this aspect of it. Rose was avoiding telling the Doctor about whatever incident had resulted in her control of the so-called vortex energy—just like she hadn't wanted to announce it to the Avengers as a whole. There was something unusual about it, almost suspicious, and Cas couldn't help but wonder whether even Fury knew the source of his most recent superhero's abnormality.

"Oh! Yes, well, that'd be the new regeneration." The Doctor's hands flew to his face, stroking down it as he spoke as if he was alarmed by the presence of his own cheekbones. Words then continued to pour out of his mouth—apparently, if he wasn't utterly mute, he had to be babbling. "Blimey, it has been a while, hasn't it? You look different, too, all grown up—not that you weren't before, but, well, your hair's gotten longer, and you look—well—beautiful, really."

Both of them flushed slightly, and Rose laughed, turning her head away slightly but still clutching his arms. He shook his head in utter bewilderment, looking absolutely content for one pure moment. Then his eyes widened and his jaw dropped as he took a half-step back.

"The TARDIS—I've still got Koschei—er, I've still got the Master in there, I—"

"The TARDIS won't be a problem," Fury reassured him, looking less impressed than the rest of them by the tear-jerking reunion. "Tyler, you're able to manipulate time as well as space, correct?"

"Yeah." She ducked her chin a bit, clearly ignoring the Doctor's baffled expression. Cas's eyes narrowed—there was definitely something odd going on here, but he was hardly about to comment on it. The unusual instant passed moments later, in any case, as Fury nodded and stepped forward, drawing the attention to the front of the room once more, though the Doctor and Rose didn't cease sending eager, playful glances back and forth.

"So the Doctor can easily be redelivered to any point in his time-stream after we're done with him. Miss Tyler, it will be your job to debrief him on the job we have, and that's to be done before tomorrow. It's getting late now, so you'll all be transported back to where you're staying. While SHIELD is being rebuilt, Mr. Stark has been kind enough to offer up his own personal tower as living quarters."

A small noise of protest came from Steve, but he cut himself off before forming any more articulate objections. Sherlock raised an eyebrow, looking more than a little disgusted, but made no comment.

"None of you will be disappointed, trust me," Tony chuckled, getting to his feet before any of the rest of them. "It's close enough to here, too—less than an hour away by heli."

"Wait—more helicopters?" Dean demanded. Cas glanced over to see that the hunter's face was notably paled at the mere thought, his fingers tightening around his jeans. "There's no way in hell I'm getting in one of those things again."

"You're going to have to get used to it, Winchester," Fury retorted.

"What—but—man, no. I'm not—no!"

"No isn't an option."

"But—" Dean began. Before he could finish, Cas leaned forward, reaching out and gripping the terrified-looking man's shoulder. He blinked briefly, mustering up his energy, and pushed out, against the space around them. There was one moment of blinding brightness, then he exhaled, and the two of them were standing on a sidewalk in a darkened New York City, cars speeding by them with loud honks.

"What the hell…" Dean half-stumbled forward, then seemed to realize what he was doing and hastily brought himself back to Cas's side. "Was that really necessary? Where are we, even? Just—what the hell, man?" He seemed more irritated than grateful.

"It was for the purpose of avoiding the helicopter ride that you seemed so opposed to," Cas replied gruffly, tucking his hands into his coat pockets and glancing upwards. The sky, he noted, was entirely obscured by the invisible fumes of the city, disguising the blazing tapestry of stars that he knew to lie beyond it.

"Great." He didn't sound very genuine. "How did you even know where we were going?"

"I've spent a good amount of time traversing the country, Dean. It would be difficult to ever visit New York without noticing Stark Tower."

Dean frowned slightly, the expression exaggerated by the shift of a streetlight from green to vivid red. A group of young, giggly women shouldered past him, and he turned with their movement, glancing up in time to get a glimpse of the massive, several-story glass-and-metal tower looming hundreds of feet above him. His jaw dropped slowly in amazement as his eyes found the five luminous letters affixed to the front of the structure—STARK.

"Wow. That's… that's where we're staying?" he asked disbelievingly.

"It is," Castiel confirmed, then set off down the street, his trench coat blowing around his legs and Dean hurrying beside him. "The others should be here within thirty minutes or so."

"Right," Dean agreed faintly, seemingly still in awe of the building before them. Of course, for someone used to spending the night in the cheapest motels he could find, it was a fantastic luxury, even more so than it would be to the average person off the street—and there were very few who deemed Stark Tower unimpressive. "What do we do until then? Do you have, like, a key to let us in?"

"Why would I own a key to the home of Tony Stark?"

"I dunno—just… what are we supposed to do?"

"Wait." Cas paused and stepped over to the wall of a dark café along the sidewalk, settling there for the time being. "For the rest of them to arrive."

"What? Out here?" Dean frowned but moved to stand beside the angel, the eagerness dropping from his tone. "For a half hour?"

"We don't have any other options right now," Castiel snapped, his patience beginning to wear thin. The least Dean could do, he figured, was at least show a bit of gratefulness for the fact that Cas thought to transport him in order to avoid the nausea and fear associated with aircrafts. But the hunter seemed insistent on complaining about everything he could think of at the moment.

"Right—fine," Dean mumbled, seemingly a bit taken aback by Cas's loss of patience. "Just… it's kind of cold out here, you know. Being practically winter and—"

His words were cut off as Cas's trench coat went flying into him—it would have hit him in the face if he hadn't managed to lift his arms up and catch it reflexively just in time. He stared down at the pale fabric for a moment, utterly confused, then looked up with a sort of blankness in his eyes.

"Hey, you don't have to…"

"I can't feel the cold," Cas replied crisply, which was true. Still, he felt rather strange without the familiar shape of the coat around him—exposed, almost, in his white shirt and tie, standing in the middle of the blazing chaos of the country's most populous city. "Next time," he added, "do not take your coat off in the conference room."

"Oh, yeah—it's still on the chair, isn't it?" Dean laughed slightly, pulling the arms of the coat on over his thin T-shirt. It didn't quite fit, but at least did the job to cover his arms. "…Thanks, then."

Castiel decided not to reply. Words were unnecessary.


It was forty-three minutes later that the others arrived, Clint with the grudging message that Fury was slightly annoyed at Cas's sudden departure and demanded he didn't do anything similar in the future.

Tony led them around to Stark Tower's entrance, complaining more than a bit about how cumbersome it was to have to use the "ground door," and they were let in by a polite but tired-looking blonde woman introduced as Pepper Potts, before Tony sent them towards the elevator with floor numbers rather than those of rooms.

"As long as you don't wreck anything, do what you want with them," he had proclaimed casually, even as Pepper winced and looked on the very verge of saying otherwise. "I've actually designed a level for each of you—well, for the original team, in any case. Holmes, Watson, Winchester, Cas, you're gonna have to go in pairs, but other than that, go wild. Stay to your own level, though. Nobody on the roof—especially not you, Clint."

And now Cas and Dean found themselves on the ninth floor, which was a wide, generally unfurnished space, deemed the "guest area" by Tony and Pepper. It featured two king-size beds up near the windows, which could apparently be tinted on command to disguise the wash of city lights that stood out like a million beacons against the dark blue night, as well as an absurdly long couch and a wine bar that Dean was far too interested in.

"This stuff is expensive, Cas," he commented in delight, holding a particularly slim, elegant bottle up to the light. The liquid inside of it caught the glow, causing it to gleam a dark violet-red. The hunter laughed lightly and set it back on the granite countertop with a clink.

"I thought you preferred beer over wine," Cas replied, sitting on the edge of the bed and watching pensively.

"Well, it's what I can get most of the time, what with our money," Dean acknowledged, turning and opening the cabinet to remove a thin-stemmed glass. "Man, this guy has got to be loaded."

Cas raised his eyebrows as Dean whistled slightly, pouring a stream of the dark liquid into the glass and lifting it as if in a one-manned toast. "You know, this place might not be so bad after all, at this rate. Here's to saving the world again, right?"

The angel dipped his chin in acknowledgement, and Dean grinned, tossing back the alcohol in one long gulp—it was not, Cas thought, the proper way to drink wine, at least from what he knew.

It was nice, though, to see Dean happy. Nice and rare, and Cas really couldn't be blamed for staring like he did.