The timing might be a little weird: Bones is still pregnant with her first child, so it's set season 7ish. But Castle and Beckett have been dating for about a year now, so that's in the end of season 5/beginning of season 6. I didn't put it under 'crossovers', because I have the feeling people read them less.

This story involves BB, Caskett, Esplanie and a bit of Hodgela. (That's how you call them right?)

Sorry if there are mistakes in it, English is not my first language.

Disclaimer: I don't own the characters of Bones and Castle, only the minor characters I put in this story.

Enjoy!

Chapter 1

"Bones? Bones! Dead body waiting for you!" Booth yells.

He hears the toilet flushing and Brennan, heavily pregnant, comes out of the bathroom.

"I highly doubt the body will be waiting for me, since he or she is already dead, Booth," she states matter-of-factly. Booth smiles at her reaction. Then he walks towards her, wraps his arms around her waist and gives her a sweet kiss.

"Never mind, Bones, let's just go."

xxx

The crime scene was an apartment on 7th Street SW. When they arrived, Cam and the rest of the team arrived as well. They saw that the fire department was present and one of the firemen approached them.

"Hi, I'm John Howard. When I and my team came up here to extinguish the fire, we discovered the body. We don't know who it is yet. Apparently, she just moved here and the name hasn't been changed yet in the register and the landlord didn't remember who lived here now, since there are so many tenants in this building and he couldn't figure out what face belonged to what apartment."

"And why exactly are we here if the deceased was killed in a fire?" said Cam.

"Don't know, we called the police and one of the officers that came here apparently thought we needed you. Oh, and we have yet to discover the cause of the fire, but we'll try to stay out of your way. Follow me."

They all walked into the apartment and saw the body lying there.

"Well, now I understand why the officers called us in," said Booth, "no way that this guy fell this way, someone positioned him like this. In other words, somebody killed the poor guy."

"Woman," Brennan stated.

"What?"

"It's a woman, and from what I can see she was in her early 'til mid-twenties." Then Cam crouched down next to her.

"I think she was strangled but we'll have to bring her to the lab for confirmation. In the meanwhile, Hodgins, can you look for anything that might indicate what was used to strangle her, of fibers from the killers clothes, you know… stuff? I think Booth was right, this wasn't an accident."

He nodded.

"Okay, guys, let's go back to the Jeffersonian."

xxx

Later that day, at the Jeffersonian

"Yep guys, I'm sure, she was strangled. Dr. Brennan, can you investigate her body further for any other marks?" Cam asked.

"I'm on it, Cam," Brennan replied. Just then, Hodgins walked in.

"Hey guys, I found a few fibers that could belong to a rope or something, but other than that, the killer didn't leave anything. I'm not drawing any conclusions yet, but this guy could be pretty pro." Then he walked to his own lab in order to find out what kind of fiber it was.

Booth walked towards Brennan. "You know what I can't figure out?" he started.

"No, what?" She was listening, but kept on looking at the remains.

"Just… First the killer strangles her, then he positions the body like he feels remorse and then he sets the apartment on fire. I just don't get it."

Brennan turned away from the remains in front of her and looked him in the eyes. "You'll figure it out. We'll figure it out." Surprising Booth, she grabbed his hand, put it on her belly and with her other hand she caressed his cheek. "Don't worry." She let go again and turned back to the remains of the young woman. Cam pretended she didn't witness this private moment, but she was once again reminded of what a great couple those two made.

Hodgins and Angela walked towards them at exactly the same time and they both started talking. Hodgins, being a gentleman, signaled that she could talk first. Angela flashed him a smile, and then smiled.

"OK, so, I've got an ID on our victim. Carla Robinson, 24 years old. She was a hairdresser, and… oh, she was getting married." Her face saddened. Poor innocent girl she thought whole life in front of her, and then… She was interrupted of her thoughts by Hodgins, who spoke next.

So, I took a closer look at the fibers, and they're from a 3-strand, twisted quarter-inch rope, made from green and white nylon."

Suddenly, recognition hit Cam. "Young, blonde woman, killed in her apartment, funereal positioned, killed with a rope made of white and green nylon… Guys, I know who did this."

They all looked at her, expectantly.

"It's the triple killer!"

Booth was the first one to reply. "I remember that case," he said slowly, "but wasn't that in New York? And he didn't set the apartments from his previous victims on fire, did he?"

Before Cam could reply, his phone rang. "Booth." He nodded a few times. "Okay, thanks Howard." Then he hung up.

"The fire was an accident. It was just a candle that was near the door. They think it fell because someone slammed the door shut. He didn't mean to start a fire. Cam, I think you're right. 3XK is here. I'll call the NYPD, maybe they can send the squad that worked on this over here. We can use all the help we can get, because from what I heard, this guy's a tough one."

xxx

In New York, at the loft

Kate's phone rang. She groaned. She tried to pick it up, but the 2 arms around her tightened their grip. Very carefully she removed them so she could pick up the phone. "Beckett. Yes Sir. We'll be there as soon as we can. OK, bye Sir." She hung up.

Her voice had woken Castle up as well. He'd heard the end of the conversation. "Kate, it's only…" he paused, reaching over to his nightstand to check the time. "6 AM. Stay in bed for a little longer, pleeease?"

"I can't. We can't. That was captain Gates; she said it's an emergency. And I think she meant it. So, stop whining and get up." She gave him a kiss and then stood up and walked into the bathroom, closing the door behind her.

He sighed, not wanting to get up. He did, though, so he could make some breakfast before they had to leave.

Not long after that he stood in the kitchen, fully dressed, making French toast. He heard her approach him, but didn't turn around. She put her arms around him from behind and kissed his neck. He turned his head a bit then, to give her a kiss.

"Morning. Sit down, breakfast is almost ready."

Within less than 15 minutes, they'd finished breakfast and they were both ready to go.

xxx

When Castle and Beckett entered Gates' office, they were surprised to see that Lanie, Ryan and Esposito were there as well.

"Sir, what's this about?" Kate asked.

"Sit down, and I'll tell you," their captain replied. Then she continued.

"I just got a call from the FBI, asking for your assistance on a case there. In Washington."

"In Washington? FBI? Why would they do that?" Esposito didn't get it, nor did the others.

"If you'd let me finish, please, detective Esposito… It's not just any case. Earlier this day, or night, they discovered a body in a burnt apartment. The victim was a young, blonde woman, who was killed with a rope made from green and white nylon, positioned as if she was lying in a coffin, and…"

Again she got interrupted, but this time by Castle.

"The triple killer? But he didn't set apartments on fire. Are they sure it's him?"

"I wasn't done talking yet, Mr. Castle. The fire was an accident. A candle fell, probably when the killer slammed the door shut. They asked for your assistance, since you handled the case a few years ago. And I order you all to go to DC immediately. Now go home and pack your bags. I already took care of the tickets. You have to be at the airport in an hour. You're dismissed."

The five of them stood up, shocked. They all thought the same: 3XK? He's back? In Washington?

The ride to the loft was silent, which was very unusual. When they arrived at the loft and stepped inside, Kate suddenly felt the need to be held. So she wrapped her arms around Rick and held him tight.

He didn't ask, because he understood. After a minute or so, he released her. "Come on, let's pack our bags."

35 minutes later, they arrived at the airport. They were the first, so they sat down on a bench and waited. The buzz from the people around her allowed her to think. Think about the past year, and how wonderful it has been. She was really glad she came over to him that night one year ago. She smiled. God, that night was unforgettable! They'd been together ever since. Of course they'd had some minor arguments, and also a very big one, but it turned out well. She moved in with him a little over 4 months ago. Again she smiled as she thought back. It was Christmas when he'd asked her.

* Flashback *

They were sitting together: Alexis, Rick and Kate on the couch and Jim and Martha both sat on a big chair; Jim on the side where Kate sat and Martha on the other side, close to Alexis.

"Time for presents!" Castle exclaimed excitingly. Kate rolled her eyes at this. He was such a man-child sometimes. But she loved him anyways.

After a while, all the presents had been opened, but then Rick went into his study. He came back with a small, rectangular box. He handed it to Kate.

She was confused. He'd already given her something, what could this be?

Carefully she unpacked it. Then she removed the lid. Inside it was a key. It had a little photo frame hanging on it in the shape of a heart. Inside it was a picture of Rick, Alexis and herself. She looked up at him. Was this what she thought it was?

He took the key out, placed it in her hand and then folded his hands around hers.

"Kate, I love you, more than anything in the world. I love waking up next to you every morning. I love to see how you move around the kitchen so easily. I love how you fit in this family and I'd really, really like you to move in with me."

Tears formed in her eyes and she nodded yes, before kissing him. They pulled apart when Alexis squealed and got up to hug Kate.

"Dad's not the only one who loves you, Kate. Grams and I do as well. You're like the mother I never had, my big sister and best friend all at once. I love you, Kate."

"I love you too, Alexis, I love you too."

* End of flashback *

Then she saw Lanie and Esposito coming towards them, Esposito having his arm possessively around his girlfriends' shoulders. She smiled. Again. She was so happy they were together again. They were a perfect couple.

Not a minute after that, Ryan arrived as well.

They all stood together in a circle, and Castle pulled them all in for a group hug. "This time, we're going to catch him. And I'm not going home before we do."

They all agreed with that. Very soon they were on the plane, beginning the trip to end this for once and for all.

Okay, this wasn't really Castle/Bones, but more Castle and Bones. That will change, however. I'm not really good at case stuff, but I hope you keep reading, because there will be cute moments as well!

Please let me know what you think!

-xxx-