Hi, guys! I'm back... with a brand new story on top of all. I know it's kind of weird but I totally adore both "Castle" and "Gossip Girl" and I thought that I definitely have to put them in one story. So, here it is. It happens after Castle's season 5 finale and Gossip Girl's season 3 finale but neither Chuck nor Blair went abroad.

I hope you like it!

"An Affair To Die For"

Chapter 1

She woke up and felt two strong arms wrapped around her. She looked around. They were in his bedroom. The blankets were wrapped around their naked bodies. A smile was spread across her face.

"All I want is you!"

The memories from last night burned in her brain and she realized that he was everything she needed to feel happy… to feel alive.

She turned and saw his face. His dark blue eyes were peacefully closed and his lips were curled into a light smile. She ran her fingers through his hair and her hand rested on his cheek. He kept sleeping peacefully, but his smile widened at the touch of her hand.

She giggled quietly and carefully got out of the bed. She put some clothes on and exited the room. She found her way to the kitchen and started making coffee.

He was sleeping peacefully in his bed. His brain was replaying moments from last night. It looked so real that when she touched his cheek, he actually felt it. He smiled widely. But suddenly he felt emptiness next to him. He turned a few times but it was useless, the other side of the bed was empty.

Horrified, Castle woke up, hoping that the last few moments were just a bad dream. But then he turned and just like in his dream there was nobody, lying next to him. Was it possible that it was all a dream? 'No way,' he thought, 'it felt so real. There's no way it was just a dream,' he convinced himself. But sneaking out wasn't much Beckett's style. Or maybe it was? As much as he spoke of how well he knew her, this one thing he didn't know.

He panicked. What was he supposed to do? If it was just a dream and he asked her why she sneaked out, it would be… awkward. And if it was all real and he didn't say a thing to her, she would think that he didn't like it and doesn't have any feelings for her, which totally wasn't true. He was absolutely hopeless when he heard her voice calling, "Wake up, sleepyhead!", and she entered the bedroom with a cup of coffee in each hand and wearing… his shirt?!

"So, it wasn't a dream," he smirked and she giggled, handing him a cup of coffee.

They drank their coffee in silence and then put the cups on the nightstand by Beckett's side on the bed.

"Did you like it?" she asked and they both knew that it wasn't the coffee she was talking about.

"Yeah," he nodded.

"Me too."

"And do you want us to… continue?" he asked innocently.

"Absolutely."

"Me too."

With those words, he kissed her passionately and she kissed him back. His hands roamed along her back, while hers were playing with his hair. Their make-out session was interrupted by Kate's cell-phone, which somehow happened to be on the nightstand by Castle's side. He groaned and pulled away from the kiss.

"Leave it," Beckett said and kissed him again. They tried to ignore the noise but it was getting annoying and was totally killing the mood. So, finally Rick took the phone and without thinking or looking at the screen, he answered it and spoke, "Kate Beckett's phone, Richard Castle speaking… Oh, Captain Gates!?"

He turned and saw Kate's eyes growing bigger and bigger. "Yeah, she's… she's right here," he spoke into the phone and then handed it to Kate. "Captain Gates," he whispered and she rolled her green eyes.

"Beckett… Yes… Yes, I understand but I thought I was perfectly clear when I said that I resign."

Castle looked at her in surprise. She hadn't told him that she had resigned.

"I'm not sure I…" she spoke into the phone, ignoring Castle's look. "Look, I… Yes… Yes, Sir. I will be there in half an hour."

"What was that all about? You resigned?" Rick asked when Kate ended the phone call.

"I'll explain on the way to the crime scene."

"She what?" Castle asked in surprise. "Begged you to come back and investigate?"

"She said that there weren't enough people and this case was very important," Kate answered without losing her concentration on the road.

"What is so important about this case?"

Beckett didn't answer but only stopped the car in front of a big building with the sign 'Empire'.

"The crime scene," she said.

"A murder on the Upper West Side? This will be so much fun," Rick said and got out of the car.

"Why?" Kate asked.

"It's the richest neighborhood… Well, not the richest if you count Upper East Side but still," he explained as they entered the hotel. "And as I have said the murders of the rich are the sickest murders of all," he said when he and Kate entered the elevator and she pressed the button for the 9th floor. "I bet the victim's some beautiful young woman who was a lover to a millionaire. The wife found out and tortured and killed her in some painful way – strangling, shooting like fifteen times or even better – she set all of her husband's lover's designer shoes on fire while she was watching and then she simply killed herself! What are you saying?"

Beckett only rolled her eyes at his question. He chuckled and put his hand on the small of her back. She quickly snatched it away.

"Do I have to remind you that no one knows about our… situation and I would prefer it if it stayed this way because as much as I enjoy it, if Gates finds out, she would have both of us kicked out!"

"Then we will have more time for ourselves," he said and tried to kissed her but the elevator doors opened and she stepped into the hallway before he was even five inches away from her.

The officers in the hallway greeted them and Castle stopped to greet them, too, while Kate only nodded and smiled towards them and went to talk to Gates.

"Sir," Kate said when she reached her.

"Detective Beckett," Gates returned the calling. "Thank you for coming so quickly," she added and handed Kate her batch and her gun.

"Thank you," she nodded.

"I see you brought Castle, too," the Captain said not approving as Castle joined them and smiled.

"Well, there was no way I didn't tell him since… well," Kate said and her cheeks rosined a bit at the thought of the phone call.

"What exactly were you two doing together when I called?"

"We… Uhh…" Castle began but Beckett cut him off.

"I stepped by at Castle's for Saturday breakfast," she said. "Right, Castle?"

"Yeah," he nodded. "It's our tradition to have breakfast together every Saturday," he explained and smiled innocently.

"Mhm…" Gates said unbelievingly and eyed them suspiciously as if something in their looks would tell her if they had been doing something… bad.

Castle saw this and asked, "So, where's the victim?"

"Room 915," the Captain replied, still eyeing them suspiciously, and motioned to an opened door. Castle and Beckett entered the room. Detective Ryan, Lanie and surprisingly Detective Esposito were already there. Castle greeted them all with a smile and looked at the victim.

"What the hell is this?" he asked in horror. There was a girl lying on the floor. She was dressed in an extremely short black dress and there were high-heeled shoes on her feet. She had long blond hair (too long, not to have been with extensions), spread around her. Maybe she would have been beautiful if it wasn't for her heavy make-up that made her face look like a raccoon's one and simply terrified Castle.

"It's a girl, Castle," Lanie answered his question.

"Cause of death?" Beckett asked, ignoring them.

"Oh, no! Don't answer that question," Rick held his hands up in the air when Lanie parted her lips to answer her friend's question. "I know what happened!"

All of the presents in the room looked at him in expectation with their eyebrows raised.

He smirked and said with triumph in his voice, "She was strangled with her own hair extensions!"

Kate looked at him unbelievingly and he said, "I'm a genius, aren't I?"

Ryan and Esposito chuckled and shook their heads while Beckett only rolled her eyes maybe for the fiftieth time today (and it was barely half past eight in the morning!) and turned to her best friend, "Lanie?"

"She was shot," Lanie said and turned the body to show three bullet wounds on the back.

"When?"

"Judging by the body's temperature, I'd say between eight and twelve last night but I'll know more after the autopsy."

Beckett nodded and said, "OK. Thanks. We'll meet you at the precinct. Come on, Castle!"

He smirked at himself and waved goodbye to his friends and then followed Beckett out of the room. They were almost in front of the elevator doors when a tall dark-haired young man, barely twenty years old, dressed in a perfectly tailored black suit, light purple shirt and a purple tie, appeared in front of them.

"What the hell is going on here? And who are you?" he asked angrily.

"I'm Detective Kate Beckett from NYPD," Kate said, showing her batch. The man eyed her head to toes. "This is Richard Castle," she motioned to Castle, who only smiled lightly. There was something in this guy that Rick didn't like. Maybe it was the way that he was staring at Beckett… his Beckett. "We're to investigate a murder. And you are…?"

"The owner of the hotel," the man stated and both Castle and Beckett looked at him in surprise. Wasn't he too young to own a hotel? "And as such, I advise you, Detective Beckett," the man began, "to do your job and investigate as quickly as possible and not to comment anything in front of the reporters, who have already circled the building."

"You don't have to worry," Kate said. "I will be as discreet as possible."

With those words she and Castle went away and left the man to stare after them… after her, if we want to be more certain.

"The victim's name is Jennifer Humphrey," Kate said as she put Jenny's picture on the white board. "She's seventeen years old, her family's from Brooklyn, but her father married a dead billionaire's wife and they moved to Park Avenue. She signed up in the 'Empire' hotel two days ago."

"If she lived on the Upper East Side and on Park Avenue, in particular, what was she doing in a hotel?" Castle, who had sat on one of the desks, asked.

Beckett shrugged her shoulders, "I guess we'll have to find out."

Rick nodded and his cell-phone rang. It was Alexis. He looked to Beckett as if searching for a permission to answer the phone. She nodded.

"Hello, sweetie," he spoke into the phone.

"Is it true?" he heard his daughter's voice.

"What to be true?"

"That Jenny Humphrey's found dead in the 'Empire'?"

"How… How do you know?"

"It's all over Gossip Girl!"

"What?" Castle asked confused. That was the first time he ever heard of that thing.

"It's a blog," Alexis replied. "But is it… Is it true?"

"Yeah, it's…" he said but silenced because Esposito appeared and said, "The victim's relatives are here."

"I'll… I'll call you later," Rick spoke into the phone and hung up.

He followed Kate into the room, where they normally met the family of the victim. They were already used to see different people in there - young or old, men or women, blond or brunette, but they were all extremely sad about their loss. This time was no exception. There were four people in the room. A blond woman in her early forties dressed with impeccable taste and a dark-haired man, around the woman's age, were sitting next to each other. On the other side of the woman were sitting two young men with not more than two years age difference. One of them looked a lot like the woman and the other one – like the man.

"Hello," Kate said and sat down. "I'm Detective Kate Beckett. This is Richard Castle."

Castle nodded to the family and sat next to Kate.

"You're Richard Castle?" the young man that looked like the older one asked. "The writer?"

"Yeah," Rick simply answered.

"I'm Dan Humphrey, a fan," he said and extended his hand to shake Castle's one. "I'm… I'm Jenny's brother."

"Eric Van der Woodsen," the other young man introduced himself. "Her step-brother."

"Rufus Humphrey," the older man said. "Jenny's father. And this is my wife Lily," he added, motioning towards the blond woman, who asked, "Is it true? Is Jenny really dead?"

"I'm sorry for your loss," Kate said. The family nodded.

"Mr. Humphrey, do you have any idea why your daughter has been in the 'Empire' hotel for the last two days?" she asked.

"No, I… She was supposed to be in Hudson with her mother."

"We didn't even know she was back in New York," Lily said.

In that moment, another blond woman, maybe Dan's age, entered the room.

"Mom, I just got your message. Is it true?" she asked.

"Detective Beckett, Mr. Castle, this is my daughter Serena Van der Woodsen," Lily said.

Serena turned to Castle and Beckett and smiled politely. "But is it true?" she asked again.

"Yes, honey. I'm sorry," her mother said.

"Were you and Jenny close, Ms. Van der Woodsen?" Kate asked.

"Not lately. She did some things that… ruined my relationship. We didn't get along well for the past month or so but I would never want something like that to happen to her," Serena explained.

"Where were you between eight and twelve last night?"

"We were all at a charity event at the Met," Lily said. "Until about eleven. Then we went home."

"You don't think that one of us did it, do you?" Eric asked.

"Mr. Van der Woodsen, it's just a routine question," Beckett said. "Can anyone confirm your alibi?"

"There were a lot of people that saw us on the event and Vanja, the doorman in our building, can tell you what time we arrived home," Lily said calmly.

"Did Jenny have a boyfriend?" Kate asked.

"Not that we know of."

"Do you know anyone that might have wanted to hurt Jenny?"

"Maybe you should talk to Chuck Bass and his wicked ex-girlfriend Blair Waldorf," Dan said. "They-"

"Dan!" Serena cut him off. "Neither Blair, nor Chuck would ever do that!"

"Serena, honey…" Lily tried to comfort her daughter.

"Who is Chuck Bass?" Beckett asked.

"He's my dead husband's son. I adopted him last year after his father's dead," Lily said.

"Okay," Kate said. "Thank you very much and once again we're very sorry for your loss. We'll do everything we can to catch the killer," she added as she and Castle exited the room.

The minute they did that Castle took out his cell-phone and started checking something in Google.

"They are a strange family," Kate said. "I'll have someone check their alibi though I don't think one of them did it. I'll also call Ryan to check this Chuck Bass and the girlfriend."

"You don't have to do that," Castle said and she looked at him in surprise. He held up his phone so that she could clearly see the web-page from the blog Alexis had told him about. There was a heading saying 'Spotted: Chuck Bass and Blair Waldorf…'. Below it there was a picture of a young beautiful brunette and a dark-haired man, both were barely twenty years old.

"Does he look familiar?" Castle asked and smirked.

So, thanks for reading! I hope you liked it.

Do you think Chuck did it? Or maybe Blair?

I know who killed Jenny and if you are curious to know it too, leave a review and let me know if you want more!

xoxo