A/N: Hey everyone. This is my first Castle fan fiction. It's like an episodic fic (that takes place between episodes) and this takes place in season 3 so Castle is with Gina, and Beckett is with Josh (but they aren't heavily involved). There is swordplay between Caskett. Anyway, I hope you enjoy and I will try to improve my writing.

Also, I do not live in New York, nor am I a doctor. Forgive my inaccuracies.

Summary: When the bodies of two sisters are found brutally murdered, it is up to Beckett and Castle to unravel the sisters mystery lives to catch who killed them, and why. Meanwhile, Beckett loses two important possessions, which makes Castle see a completely different side of the Detective.

Disclaimer: I DO NOT OWN ANYTHING.

CHAPTER ONE

THE flashing red and blue lights of the two police cruisers lit up the night sky as Detective Kate Beckett pulled up her unmarked police car on the opposite side of the road.

Already, people had started to gather around the now blocked off crime scene, hoping to get a peak at what lay ahead - some taking pictures with their phones, no doubt planning on Twittering or Facebooking to their friends or followers at what they were seeing, or trying to see - while the officers tried their best to keep the curious, and often nosey, pedestrians at bay, who only stopped to stare because the daily routine of their mundane lives had been shaken up.

However, Kate knew all to well what laid beyond the yellow tape she hated so much. To her, it wasn't just a body that people were shoving themselves to get a picture of. It was so much more. It was a life, and now it would become a tragedy to the family and friends that knew the victim, and whose lives would never be the same again.

Getting out of her car, and shutting the door, she walked across the street, putting on the purplish latex gloves everyone who crossed the tape was required to wear, while pushing herself through the crowd of people. She flashed her badge to one of the officers who just nodded their head, and for a brief moment, as she held the yellow tape over her head, like many times before, she remembered that awful night ten years ago when her world was destroyed.

She shook off that sinking feeling in the bottom of her heart, as she fully crossed the threshold. No one would know, or could know, just how much her mother's murder had damaged her.

"Good evening, Beckett." She heard Castle say, who was suddenly now beside her with a tray of coffee in his hands. One cup for her, and one for him.

"Castle," She responded, in her usual way that was a mix of 'what are you doing here' and 'it's nice to see you', as she took the cup of coffee from him.

In the beginning of this Mayor-supported relationship that had Castle shadowing her on cases for the purpose of character inspiration for his next book, so he could write another hit series that would parallel his greatest hit, Derrick Storm (whom he had killed off in his last book), she resented his presence. To her, Richard Castle was like a nine-year old on a sugar rush, totally incapable of taking anything seriously. Now, after almost a year and half of working with him, she still thought he was a nine-year old on a constant sugar rush, but she found that she didn't resent his presence so much, and, embarrassingly, enjoyed his company.

"How is it that you always arrive at crime scenes faster then me?" Beckett asked as they made their way further into the secluded ally that was nestled between a Chinese Food Store and Joe's Pizza Place, both of which now were abandoned.

"I was in the area," Castle said as they stopped short in front Lanie Parrish, the Medical Examiner, who was overlooking two bodies, each with their backs exposed.

"There is two of them?" Beckett asked, exchanging looks between Castle, Esposito, Ryan and Lanie. "I thought the call was only for one homicide."

"While gathering for evidence, CSU found the other body in that dumpster," Ryan said, pointing to the one on the far left.

"And the homeless man who called this in, found this body in that dumpster," Esposito added, pointing to the one they were all standing in front of.

"It gets weirder," Lanie said for the first time that night.

"I like weird," Castle said, giddy-like.

"You ready?" Lanie asked, and the three detectives, plus Castle, nodded their heads as Lanie turned the bodies over.

"Twins?" Beckett asked, noticing the striking resemblance both girls shared.

"Looks like, but I won't know for sure until I do a DNA test."

"How about I.D.?" Beckett looked over at Ryan and Esposito.

"CSU found nothing, but the girls are dressed well, and they don't look homeless. Someone has got to be missing them," Esposito responded.

"I already have someone looking into missing person reports matching their description and age-range," Ryan added.

Beckett nodded her head, and then turned back to Lanie. "Any idea on the cause of death?"

"I can't say for sure until I do a full autopsy, but both girls were stabbed multiple times, and both have defensive wounds on their hands. Blood loss would definitely be a factor, and considering there is little blood at this crime scene, they were obviously dumped here."

Beckett nodded her head, and stepped away from Lanie. CSU was busy going over the whole ally, and aside from a homeless man, no one saw anything suspicious. In fact, this part of town was basically dead, with most shops out of business, and those who walked through this part of town never stayed long enough to notice anything anyway. This case, to her, was beginning to feel cold without even starting anything.

Castle had come up beside her again, trying to focus on what she was focusing on.

"This case feels like it's going to cause us trouble," Beckett commented, letting out a sigh, still staring out at nothing in particular.

"Yeah," Castle agreed, before turning to Beckett. "Double trouble." He gave a small smile, and Beckett, used to his inappropriate quips at crime scenes gave a small smile back.

"Go home, Castle. There isn't much more we can do tonight."

CASTLE shut and locked the door behind him, and quietly put his keys into what Martha, his mother, had called the 'So-we-aren't-running-around-the-house-like-chickens-with-their-heads-cut-off-bowl' bowl, that held keys, wallets, Alexis' bus pass, and sometimes, loose change. At first he didn't take to the idea, but after misplacing his keys in the refrigerator, washing/dryer machine, and God knows where else one-to-many times, knowing where his things were in case Beckett called him to be at a crime scene turned out to be a God send.

He walked into the kitchen and opened up the fridge, taking out a bottle of water. It was then, after he shut the fridge, that he noticed his mother was still up, sitting on the couch, in the dark.

"Mother, what are you doing?"

"Reliving my glory days."

Castle turned on the light, noticing old tapes scattered on the coffee table.

"Again? Isn't this like the third time this month?"

Martha only gave her son the look. "Laugh all you want, Richard. The truth is, I was in my prime back then. Now, not so much."

Castle, realizing his mother was hurting, put his bottle of water down and went over to the couch to sit with her.

"Tell me what happened," He said.

"It's silly," She responded, but Castle only pressed further. "I ran into Sheila today," She finally admitted through an exasperated sigh.

"Sheila? Since when do you take criticism from that two-bit bimbo and care about it?"

"Since she got cast in one of Broadway's most proclaimed new shows."

"That's what this is about? So she gets a chance at a maybe proclaimed Broadway show - Mother, you've had several. She can't even hold a candle to what you've accomplished."

Martha smiled to herself. Richard always had a way of making her feel better, and she was truly appreciative that she had a son like him.

"Alexis sleeping?"

Martha nodded her head. "Poor girl fell asleep with a book in her hand studying for a biology test."

"Daughter isn't right," Castle said as he leaned his back on the couch, which caused Martha to laugh.

"Definitely nothing like you, or Meredith, for that matter."

Castle smiled at his mother, and then let out an exhausting sigh. He hadn't been at the crime scene long, but there was something about this crime scene that was tiring.

"Bad crime scene?" Martha asked, after a moment of quiet had passed between them.

"All crime scenes are bad," Castle said, while closing his eyes, sounding more like Beckett then himself.

"I imagine they are," Martha added quietly.

"Two sisters - twins. What are the odds to not only be born together on the same day, but die on it as well?"

Martha used her son's knee to help herself up from off the couch. "Goodnight, Richard."

"Night," He said as he watched her head up the stairs. He leaned over to shut the light off, and for a moment, he was the one now alone in the dark.