The next morning woke Beckett bright and early. She wanted to have a good start on the case. The detective dressed quickly and made her way out into the kitchen.

Castle and the Doctor were already up and eating breakfast. The Doctor was chatting animatedly with Castle, waving his hands excitedly in an effort to explain something. Castle looked completely entranced, that adorable idiot grin on his face. The sight of it brought a smile to Beckett's own lips. Castle had changed and matured in so many ways since he'd been the callous playboy she met, but he would always have this wonderful inner child to him. It was one of the things the detective loved about him. There was just something about him that let him see the world as something to be constantly excited about.

At first, she'd thought the Doctor was very much the same. He'd acted a lot like Castle after all, always the goofball, always the one with a quick joke. But the child in him wasn't built from joy; it was built from fear, fear of something inside himself. The world wasn't exciting to him, not innocent; it was more like he forced himself to look at it that way. Like if he stopped being excited about life, stopped smiling for even a moment, he would simply fall apart.

Beckett had only known the guy for a few days, but she felt like she knew him, or at least understood him, better than that time would usually allow. They shared that pain of loss and guilt.

Shaking herself out of her thoughts, Beckett strode into the kitchen and grabbed a banana from one of the cabinets. "I'm heading to the precinct," she informed the two.

Castle looked surprised. "Already? Aren't you going to get breakfast first?"

In response Beckett held up the banana, which Castle eyed critically. She laughed at his dubious expression. "I'll grab something on the way there," she assured him. "I just want to get there early so I can call 'Detective Cage' and give her plenty of time to get there." She threw the Doctor a quick, searching glance, still vaguely hoping to see a hint of deception. There a tiny voice in her head whispering that maybe, maybe it was still all some kind of set-up. But she knew it wasn't. It was all real, and now that the shock had worn down she was starting to accept that.

The Doctor looked up eagerly. "So there's not any problems with getting me in to see Karrow?"

Beckett nodded. "I'll tell them that the charges were dropped against you as long as you agreed to help, and that you're working with Detective Cage." Her eyes narrowed into a sudden glare. "Listen, I'm only doing this because you say you can help solve Karrow's murder, so just do as I say and keep your mouth shut unless you have something valuable to contribute."

Amusement glittered in the Time Lord's eyes. "I won't say a thing," he promised. Beckett groaned when she recognized the tone in his voice. It was the same tone in Castle's voice whenever he promised to stay in the car.

She gave Castle a quick glare. "Are you sure you two aren't related?" She asked drily. Far from looking insulted, Castle seemed absolutely delighted at the thought. Shaking her head at her partner's antics, the detective slipped out of the apartment and started off for the elevator.

SCENEBREAK

When she reached the precinct, Esposito and Ryan were waiting with news. "I went over Karrow's financials," Esposito informed her as she sat at her desk. "Nothing unusual there. But, then I did a scan of his medical records."

Beckett tried not to look too nervous. "What did you find?" She hoped her partners wouldn't realize she knew more than she should.

"Nothing." Beckett blinked in surprise. "Absolutely nothing. No surgeries, no check-ups, not so much as an aspirin bought in his entire life. I called up that sister-in-law, and she said the man hated doctors with a passion. Apparently he was into all kinds of herbal remedies and such."

Beckett leaned back in her chair. "There were a lot of plants in their house," she recalled. In truth, it didn't surprise her. If Karrow really was an alien, it made sense that he wouldn't want to go anywhere near a doctor.

Ryan spoke up. "I talked to the Karrows' neighbors, and they said the family's pretty quiet. Always keeping to themselves, not a lot of visitors. No one ever saw Karrow leaving at weird hours though, so I don't exactly see him being a drug dealer. No one I talked to saw any arguments between Tanya and Karrow, but they said they wouldn't have known anyway since Karrow was such a shut-in."

Again, everything Ryan said fit with the whole alien theory. Beckett rubbed her temple, trying to block out the questions and worries pounding inside her head. She needed to focus on the case. "Right. Run a background check on that library assistant Mindy, and try to find out from her if Karrow had any other favorite haunts. A movie theater, a bar, a grocery store, I don't care. Just get me something. The guy has to have interacted with more than one person outside his family. This is getting ridiculous. Meanwhile, I'm going to call Detective Cage from the other day. John Smith is our best suspect at the moment; maybe she got him to talk."

Esposito and Ryan nodded and turned to their computers. They didn't seem suspicious at all. Beckett let out the breath she'd been holding. Normally she wouldn't shut those two out of anything, but the fact that aliens existed and were involved with the case seemed a bit too much to dump on them so suddenly.

She made a point of picking up her cell phone so Esposito and Ryan could see, even as she dialed in Castle's number. "Detective Kate Beckett, badge number 0034, I'd like to speak to Detective Melody Cage?"

A tired, groggy voice answered her. "Castle's already heading over to the precinct," River told her with a yawn. "I assume you want us to come too? Damn it, is there any coffee in this house?!" There was laughter in the background, and River's voice dropped to an irritable growl. "Zip it, sweetie."

Beckett held back a chuckle waited a few moments as though being patched through to the detective. After a few moments she continued. "Cage, have you had any luck with Smith?"

"Oh, more than you know," River chuckled sleepily, amidst the loud protest of "River!" from the Doctor in the background. "We'll head over in a few minutes," she continued in a slightly more awake tone.

Beckett nodded. "If you're sure… alright, bring him in." She hung up, trying to hide her amused smirk. Clearly River was not a morning person

Esposito and Ryan had turned back to face her, curious. "Is she brining Smith here?" Ryan asked.

The detective nodded in response. "Apparently her precinct is willing to drop the charges if Smith agrees to help with the case. They say he's some sort of coronary genius, so he might be able to tell us what's up with Karrow's results."

Esposito and Ryan shared a confused look. "What was wrong with Karrow's results?" Ryan asked.

Beckett cursed internally. She'd forgotten that she hadn't mentioned that to either of them. "Apparently something was up with his genetic structure. Lanie thought it be caused by drugs but she wasn't sure which ones," she lied quickly. Well, it wasn't a total lie. "Cage is going to bring Smith in to take a closer look. Let Lanie know we're coming, alright?"

After another weird look at Beckett, the two turned back to their computers to comply.

SCENEBREAK

Castle arrived a few minutes later, coffee in hand for his partner. Beckett accepted it with a grateful smile. "I called Cage," she informed him with a meaningful look. "She's bringing Smith in to help with Karrow's results."

Castle nodded his understanding as he lowered himself into his chair. They shared a quick look that varied in excitement and apprehension. If Cage or Smith was found out, they'd both be facing trouble. Beyond that, Beckett was still having moral reservations about bringing two liars and possible suspects in under false pretenses. Just because they showed up with a wonderful time machine and stories of other worlds didn't mean they weren't mixed up in Karrow's murder. Beckett defended her actions by reminding herself antagonizing them at all might chase them away in that blue box of theirs, and there would be no way for her to stop them.

And yet, oddly, Beckett felt herself trusting them. That strange Time Lord and his vicious partner. After she and Castle had discovered the TARDIS, the two travelers had been nothing but open about their intentions and who they were. But more than that, there was simply something so sincere about the Doctor. He might not always tell the truth, but Beckett could see from what he did that he really, truly cared. He truly felt responsible for Karrow's murder, and he truly felt remorse for a lost life he hadn't even known. That, more than anything, earned him Beckett's respect.

She only hoped she wasn't wrong.

SCENEBREAK

They only had to wait a few minutes for River and the Doctor to arrive. The archaeologist was professionally dressed, but her smirk was anything but as she strode into the precinct with her partner in tow. The Doctor on the other hand was in the same tweed-and-bow-tie look as ever. Beckett wondered briefly if he ever changed, but soon snapped into a brisk, professional manner. "Detective Cage," she greeted as she briskly shook River's hand.

The archaeologist's eyes gleamed with amusement. "Detective Beckett." She gestured back to the Doctor, who was gazing around the precinct with that child-like curiousity. "Dr. Smith has agreed to look over Karrow's results to see what conclusions he can draw if you agree to drop any charges against him," she explained.

Beckett clenched her jaw, still not at ease with what she was doing. "Agreed. Follow me." Ignoring Esposito and Ryan, who were gaping at her easy acceptance of River's terms, turned and led River and the Doctor to the morgue.

Lanie was waiting when they got there. "Ah, so this is the prime suspect you've decided to bring to my morgue," she commented drily, giving River and the Doctor a measuring glance.

River stopped to introduce herself, but the Doctor was too distracted by what he saw in the morgue. He gazed around with childlike wonder, a huge grin on his face, and it wasn't long until he was bounding back and forth, babbling excitedly about the different equipment in the lab. Lanie stared with raised eyebrows at the childish antics, but River just rolled her eyes. "Dear, can we focus on the case please?"

The Doctor paused, calming down. "Case. Right." He followed Lanie to the microscope where she had placed Karrow's tissue sample. As he examined it, Lanie explained uncertainly, "It's not like anything I've seen before. It's like he rewrote his entire genetic structure. Do you know anything that might have caused this Dr. Smith? Cause I've got nothing."

The Doctor looked through the microscope, frowning. "Hmm. No, there's no technology that could do that, not except on the TARDIS, and that's specifically designed for Time Lord use." Lanie's eyebrows rose even higher. She shared a glance with Beckett asking, Did you bring a crazy guy in my morgue? but Beckett could only shrug back helplessly. How could she tell her friend that she knew exactly what the Doctor was talking about, and that it related to aliens?

The Doctor adjusted the microscope slightly, frowning further. "The problem is, I don't recognize this. But… hold on…" Suddenly he let out a cry of triumph and clasped his hands together excitedly. He straightened and turned to a bewildered Lanie. "Show me the body," he ordered eagerly.

Eyebrows still raised skyward, Lanie turned to wheel out Karrow's body, still respectfully covered with his sheet. The Doctor grinned when he saw it. "I knew it," he gushed. He took out his sonic screwdriver, and before Beckett could stop him, he pointed it at the body and turned it on with a brisk whirr.

The body immediately changed. What had once looked human morphed into something distinctly alien. It was shorter than a human, maybe four feet tall, with gray-brown skin that was weathered like an elephant's that stretched all over its skinny body. It had long limbs, large four-fingered hands, a square-ish jaw, short forehead, tall, pointed ears like an elf with a smaller second ear behind that, wide brown eyes which were larger than a human's, an extra set of tiny eyes beside those, and a rounded, ape-like muzzle. It was alien but not repulsive, just… different.

Lanie let out a strangled noise of surprise which remarkably hadn't turned into a scream, Castle looked ready to burst with excitement, and River looked concerned for Lanie. But Beckett was focused on the Doctor, who didn't even seem to notice the others' reactions. He pocketed his screwdriver again, a satifised grin on his face. "He didn't change his genetic structure from human to alien, he was an alien wearing a shimmer to appear human. Of course his genetic structure was still alien underneath, the shimmer only effects appearance, not DNA."

Lanie gaped helplessly at the Doctor, lost completely for words, for once. She was just gathering her words when a small cough sounded behind them.

They all turned to see a wide-eyed Ryan and Esposito standing behind them, gawking at the body in shock. Ryan opened and closed his mouth a few times, but Esposito was the first to get words out. "Did… did that body just… change?" he asked weakly.

SCENEBREAK

While the Doctor and River quickly reset the shimmer on the body, Beckett sat Esposito, Ryan, and Lanie down and explained the whole story. How the Doctor, and apparently Karrow, were aliens from another world. How the Doctor and River traveled in a blue box called the TARDIS that could travel in time and space. How they were here to help with the case, and thought they could find an explanation. Esposito took a bit more convincing than Ryan, but seeing the body change seemed to be enough for them in the end. As the shock began to wear off, they both seemed to acknowledge the awesome side of what had happened. In a few minutes time they were questioning the Doctor, Ryan eagerly, Esposito still trying to keep up his gruff tough-guy act.

Lanie, once the initial shock had worn off, accepted what had happened almost immediately. "I knew there was something weird going on with that DNA." She gave a nervous laugh, shaking her head at the situation. "I mean, aliens and time travel, that's all weird and everything, but it does explain what I found." She quickly seemed to be regaining confidence, although the revelation of aliens still had her a little dazed. "So where's Karrow from then?"

"No idea!" The Doctor hurried over from where he had been talking to Ryan and Esposito. "I've never met his species. I'd have to run a few tests to figure out exactly what he is, but I think there's an easier way. We could just pop over and talk to his family." He was rubbing his hands together with eagerness. "A whole family of aliens hiding out in New York City! Of course it's not that shocking, New York attracts all kinds, but still, this is early for alien refugees to hang out on Earth. So, the question is, what exactly they're doing here, how they got there, and why there's a blade-wielding maniac after them." His grin contradicted his words.

Esposito, who had followed the Doctor back over to the group, spoke up. "They could be running from something." When the others looked questioningly at him, he clarified, "I don't know anything about this weird alien shit, but I do know that one guy and a few kids aren't going to take over the planet. They could be running from their planet or some trouble they found there." He paused for a second, then shook his head, laughing a little bitterly. "God, what am I even talking about?"

The Doctor clapped his hands, eyes bright. "Good, good idea! So, aliens running from other aliens, and they come to Earth. Why?"

Beckett almost got the feeling that he was testing them, which irked her a bit, but an answer had already come to her head. "Because we're not advanced enough to find them."

"If they're advanced enough to disguise themselves as humans, they'd be completely safe," Castle added, taking up Beckett's train of thought. "We don't have any knowledge of aliens yet, so we'd never suspect them of anything."

Beckett finished, "And this is one of the largest cities in a relatively lax country as far as civil rights goes. Hiding in a crowd."

The Time Lord looked delighted. "Brilliant! So we're going to find a small family, probably refugees, scared and hiding, especially now that it's just the kids left. We'll need to be delicate."

Beckett took control once again. "Alright, then just the four of us. Esposito, Ryan, try to figure out how to keep this from Gates. She'll be expecting an update soon, but if the killer's alien it's not likely we'll be able to arrest them." She shot the Doctor a glance at that, wondering exactly what his plan was for the killer, but he didn't say anything. "Lanie, keep looking at that throat wound. Search for anything that might have gotten left behind, a fragment of metal or something. Keep trying to figure out what caused it."

Ryan looked a little put out at being told to stay put when there were aliens to meet. "Why can't we come too?" he asked.

The detective sighed impatiently. "Karrow's oldest daughter is protective enough of her family as it is. We need as few people to come with us as possible. I'm coming because this is my case and I have questions I need to ask her, Castle's coming because he's good at interrogation and he's good with kids, the Doctor's coming because he can disable that shimmer thing and he knows about aliens, and River's coming because she keeps the Doctor from putting his foot in his mouth." Castle let out an amused snort at this, while the Doctor turned a pout on Beckett, who stared back, unimpressed.

As she stood up, she fixed everyone in the room with an unwavering glare. In a low, serious voice she told them, "No mention of aliens or time travel or anything we've discussed today will leave this room. We don't know what it is we're dealing with, and if we tell the higher-ups about this, they'll take the case, and they'll take the Karrows, and we'll never see any of them again. We're homicide detective's. We're here to find a killer and being some closure to the victim's family. I'll be damned if I let the victim and his family get carted away to some secret because we thought someone else had to know about this."

She would have added some sort of threat to the end of this, but there was no need. Lanie still looked shaken, but she cast a quick, sad glance at the victim's body and gave a firm nod. Esposito and Ryan were looking straight at Beckett with calm, determined expressions. Beckett knew they'd attack this case with everything they had now that the stakes were so much higher, and they'd never turn their back on a grieving, vulnerable family. River and the Doctor nodded with unusual solemnity, both looking at the victim with quiet sympathy. Beckett took in their expressions with a critical eye, then finally relaxed. They were outsiders as much as the Karrows. They wouldn't tell.

Castle reached out a hand, which Beckett grasped gratefully. She didn't even need to ask Castle his confirmation. That man would do whatever it took to protect this family, and he would never betray her, not even to tell his family. For a moment Beckett was almost overwhelmed by the knowledge of just how much Castle loved her, and how much she had grown to love and trust him..

She turned away from her team and headed for the door. "Alright then. Let's get back to work."

Another chapter for you all (or rather my one regular reviewer - thank you superlc529) in which I discover that the Doctor is hard to write (again), this chapter and the next definitely needed to be in Beckett's point of view so it's a good thing I switched, and River is not a morning person. And I'm guessing the Doctor once had to learn that the hard way.

So now we know Karrow's definitely an alien, and we know he was using a shimmer like the cacti-people (sorry, blanking on their names) from the End of Time. But we don't know what he is, why he's here, or why he was killed. Dun dun dun. Next chapter we'll be returning to the Karrows, which I've been looking forward to for a while.