Disclaimer: I am a caskett shipper but I don't own them so this is my way of correcting the universe.

(Set after the pizza episode and kind of what could happen with this new "partner")

Chapter 1

" Beckett this is Alex Conrad" the chief introduces the attractive man and she shakes his hand politely.

" Your new partner.." She suddenly drops her hand from his and stares blankly at the chief.

"Sir, no disrespect but I have a partner" pointing to Castle. She sits down crossing her arms and just stares.

" Castle is a wonderful help to this prescient but Alex here is an official Detective in need of a real job not just for fun." Beckett is offended after all the cases Castle solved and all he had contributed the Chief was giving him the short end of the stick.

" I don't want to intrude but I just transferred and I heard you were the best" He put on a charismatic grin but she wasn't fooled. She stood up and brushed past him saying, " I am the best which is why I don't need you."

The case that she had received before the chief introduced her was a female homicide in lower Manhattan, single gunshot execution style. She took Castle's arm pulling him away from the boys and took one of the coffees he was holding in his hands.

"Who Mr. Important over there with the Chief." He grinned at her as they got into the elevator.

"No one just my new partner" The doors began to close as he choked on his coffee.

You could hear them arguing from a mile away and it was especially annoying for Dr. Lanie Parish as she examine the body carefully.

" I am not ok with this!" Castle was following Beckett two paces behind trying to catch up.

" It isn't your choice to be ok with it and did you even bother to ask if I'm ok with it." She stopped and turned making Castle almost crash into her.

" You don't seem to have a problem with it, but are you ok with it?"

" No, I have one partner and as much as they get on my nerves I only want one." Castle's face turned into a grin. " I didn't realize you thought that." She turned around and began walking again and yelled back, "Yeah Esposito has been the best partner I've ever had." His face turned into a frown as he ran after her. " Liar Liar pants on fire."

Beckett crouched down next to Lanie to examine the remains.

" What do we got?" She notice a lack of bruising or scratches on the victim's body which suggested no sign of a struggle.

" Female, late 20's, I.D. says Alyssa Carrow…her badge says she was an RN at the local hospital. One gunshot to the head at close range execution style, I put death around 10 p.m- 2 a.m. at the earliest."

A voice from behind them said "There's no bruising or scratches around her arms or any signs of a struggle." Alex Conrad crouched down to Beckett's level and smiled.

"that's right and who are you?" Lanie looked from Beckett to Conrad.

" This is…" Beckett was cut off " I'm her new partner Alex Conrad."

Lanie began coughing on her words " her what?" Meanwhile Castle stood watching the replacement him steal his line and get close to his Beckett.

" The Chief is making me take him under my wing." She rolled her eyes and went to go talk to Castle.

" Ok so I know I just got her but what is up with those two, she has the choice between a trained detective and a mystery writer and she chooses him. How long have they been sleeping together?" Lanie was still in shock over the whole partner thing when she registered what he was asking.

" Honey they are not sleeping together, you just don't understand what they have. I can't count the number of times he saved her or she saved him or they both saved everyone else. They're like Scully and Mulder without the sex." She barely had time to finish when Conrad began running after a leaving Beckett.

" So first you don't tell me about a crime scene and now you're going to leave me at a crime scene, our relationship is moving so fast." His dry sarcasm elicited a Beckett eye roll and an over protective glare from Castle.

" You, oh amazing detective Conrad, will stay here and wait for Esposito and Ryan. We are going to talk to her family" She dismissed him but he kept following.

"Sorry but I'm your partner not theirs and I would love to see how you tackle breaking the news to families seeing as you have personal experience." Beckett stopped in her tracks. Castle didn't hesitate and slammed him against the SUV.

" I don't know who you think you are or where you came from but mark my words if you ever say something like that to her again I will end you." He hesitated to let go but Beckett pried his hands off. "Castle I can handle him." Conrad straightened his coat and scoffed at Castle. " What is writer boy going to do poke me with his pen?" He began laughing until Beckett slammed him back against the car. " Two things only I get to push him around and he's the least of your worries." His laughing stopped and he brushed himself off. " Now go help Esposito and Ryan before I kick your ass again." He turned around a scurried back to the crime scene.

On the way to the Alyssa's parents house Beckett couldn't stop staring at Castle and he noticed.

"What's on your mind?" she knew he had caught her.

"If the chief makes me be partners with him that will sever our partnership and you won't be able to shadow me anymore." She looked down from the road and a tear traced down her face.

" I'm not going anywhere who else will protect you from macho detectives?"

" Always she whispered?"

"Always."

Author's Note: This is not a one shot this will actually be probably a 10 or so chapter series. I have this idea in my head that will blow you away and it's really going to pull them together. Please keep reading it's about to get good.