Beckett's Sister: A Castle AU Fanfiction

Chapter 1

"You ready to go?" Castle asked as he grabbed his coat from behind his chair.

They had been at it since 5 am and it was now almost midnight. Kate was finishing up the last of the paperwork for the most recent case they had closed a few hours earlier.

"Yea, just a sec." Kate replied, adding her signature to the last of the forms. She placed it on top of the rest of the forms, grabbed her bag and coat, and flipped off her computer monitor.

"Are we on call tomorrow?" Castle asked her as they waited for the elevator. He was exhausted and knew she was too, even though she did a pretty good job of hiding it.

"Nope, we don't have to be in until 8. We have a new detective transferring from the 30th precinct and Gates has given me the glorious opportunity of training her." Kate said, with a slightly less than happy look on her face.

"Seriously? Well, of course she would want her top detective to show them how it's done." Castle said as they stepped into the elevator and waited for it to close.

"I should be more upset, considering I'll pretty much be stuck here all day showing her the ropes of the computer system and all that, but I remember what it's like to be the new kid on the block so I can't really complain much." Kate said as they finally reached the parking garage and made their way to the cruiser.

"Well, if that's the case then, I guess I'll write for a while tomorrow and then bring you guys lunch. I have a chapter due soon anyway and I really don't want Gina on my case." Castle said with a look of mock horror on his face.

When they finally made it back to the loft, Kate's exhaustion had gotten the better of her and after depositing her gun and badge in the office safe, she and Castle changed clothes and fell into bed where they were asleep within minutes.

The next morning, Kate's phone was going off while she was in the shower, which eventually woke Castle from his sleep. There were several text messages, which being as nosey as Castle was, he had to read.

He made his way into the bathroom just as Kate was toweling off. "Your sister is insistent that you call her when you get a chance. She's back in town and wants to know if you want to grab coffee with her on your way in." Castle handed her the phone, giving her a kiss on the cheek before he made his way to the sink to brush his teeth.

Despite a 7 year age difference, Kate and her sister were inseparable. Kristina Beckett, or Kris as she preferred to be called, was the complete polar opposite of Kate. After the death of their mother, Kate had moved back home from Stanford to finish school at NYU before going on to join the police academy. Kris was 12 when their mother died, and after their father started drinking, Kate had to pretty much finish raising Kris.

After graduating high school, Kris attended The City College of New York where she obtained a B.S. in computer science then went on to pursue a degree in computer forensics. Kris worked at the 12th as the head of tech so Kate saw her sister on a daily basis. In addition to working for the NYPD, Kris also owned a nightclub in lower Manhattan that Castle and Kate went to a couple nights a week when they weren't all working on a case.

After getting dressed and getting her stuff ready to go, Kate kissed Castle good-bye and texted Kris on her way out the door. "So, you finally decided to grace us with your presence?" Kate said a little while later when she met Kris at the coffee shop near the precinct.

"Yea, well you know I don't do the first of the year well." Kris replied sarcastically. "Besides, you had Castle to keep you company."

"He always keeps me company Kris, he's my fiance for Pete's sake. Anyway, how was LA?" Kate asked as she took a seat.

"Same as always. Bright, sunny, full of star struck people oblivious to the real world. So, what's the day look like?" Kris asked before taking a sip of her caramel frappe.

"No active case right now. Gates has me training a new detective transferring from the 30th so it's going to be a long day." Kate replied reluctantly.

"It could always be worse." Kris said. "You could always spend your day updating firewalls for the entire precinct computer network on your first day back from vacation, like I get to do today." She faked a smile, causing Kate to burst out laughing.