Hi Everyone, Knight Rider Alpha here.

It's time for another of my AU One Shots, It's time for Season Two set around the time 02x21 'Overkill'. I know again this feels like an absolute age ago but it's still fun to revisit the oldies.

Just think Sparring Sessions.

Standard Disclaimer: Not mine, Never will be. Belongs to the fantastic AWM and the guys and girls at ABC Studios.

Unleashed

It was a bright and cool early morning in the city that never sleeps, the sound of sirens and car horns filled the air and even at this early hour many New Yorkers were beginning their days.

The elevator dinged on the fourth floor of the 12Th precinct, Detective Kate Beckett stepped out her heels clicking against the floor and she walked towards her desk. Dropping her bag into her bottom draw as she reached into her pocket for her phone having felt it vibrate.

Reading her message that had appeared on screen she smiled.

"I had fun last night, We should do that again sometime. Tom xxx"

Detective Tom Demming a Robbery Detective at the 12Th who had helped on a recent case for the team was funny, charming and handsome. Kate had immediately accepted his offer of dinner the previous evening to a little Italian place on Broadway, The conversation was light and happy with very little shop talk.

Kate had taken to him much to the trepidation of the writer who at every chance he got tried the game of one-up-manship with him, Kate could sense a change in her feelings towards Castle he had grown from the nine year old on a sugar rush to a useful and essential member of the team.

But his jealous routine was starting to grate on her.

'I don't have to justify myself to him, I can do what i want' she thought taking a seat of her desk booting up her computer.

That was when it hit her a full sensory overload, The distinctive smell of cologne surrounded her however something was strange it smelt like the kind Castle wore. She stood up from her desk and followed the scent, Her mind wondering why Castle would be here so early normally she was the only one here this early.

She tracked the scent down the back stairwell that led to the precinct gym directly two floors below, She noticed the door was slightly ajar and the sounded of movement could be heard inside.

As she approached the door she peered through the window she eyes widened.

A male figure dressed only in loose fitting shorts was practising a series of high intensity pull ups on a horizontal bar, The sheen of sweat on his heavily muscled body was clear in the yellowish glow of the florescent lights overhead. Soon enough he dropped the ground back still to the door, Picked up a set of hand weights starting a quick series of bicep curls.

Kate's mouth slightly open touched her fingers to her lips she couldn't peel her eyes away from the man inside, The play of his muscles under skin the fibes almost visible the strength possessed inside ready to be unleashed. The heavy weights looked like they were made of paper in his hands, Soon he stopped his free weights before walking over to a gym bag on a nearby bench.

She noticed him pull out two metal cylinders before screwing them together, He spun the completed staff around his body before walking towards an empty sparring mat taking a stance. Soon he sped through a complicated series of movements, The staff spinning around his body at an incredible speed not once did the metal object touch him.

Striking a final stance he finished facing the door, Kate's eyes widened in absolute shock.

It was Castle

'Oh my god' She thought, Never once had she thought the writer had this much skill 'I wonder why he never told me" She finished

She was broken from her thoughts by an alarm sounding from Castle's gym bag, The writer stood to his full height and walked over breaking down his staff and packing it away as she turned off the alarm. He grabbed his bag hefting it to his shoulder before walking off towards the showers.

Taking this as her cue to leave slowly made her way back upstairs, Again her thoughts still reeling from what she had witnessed in the gym only moments ago. The journey to her desk was a blur her mind still couldn't believe it, Her eyes were captivated by the sight of Richard Castle world famous bestselling author had the clear skills of a veteran marital artist.

Shaking her head clearing the visions logged onto her computer, Pulling forward a Manila folder and opening the front to view it's contents starting her paperwork. Soon enough Esposito and Ryan entered the bullpen, Making their way to their desks engaged in an animated conversation about last nights Knick's game.

An hour later the elevator dinged and dressed in his standard and expensive suit Richard Castle strode toward her desk, Placing her coffee cup within easy reach along with a Bear Claw pastry as he took a seat in his usual chair.

"Good Morning Detective" He said jovially

Beckett smiled as she reached for her cup taking a long sip enjoying the fine brew, The coffee had become a staple between them in recent months.

It was their thing.

"Morning Castle, Your here early"

"Well i had to fulfil my coffee obligation" Said Castle smirking

Kate just rolled her eyes taking a bit of her pastry unknown to the duo they were being observed, Two eagle eyed Detectives were looking at the pair behind the glass of the Homicide Break Room.

"Hey Bro, Check this?" Said Esposito getting his partners attention "Is it me or does Beckett seem happier this morning?"

Ryan peered through the glass to see Kate laugh at something Castle had said "Maybe she had a date last night?" Said Ryan cyptically he had overheard the Robbery Detective ask her to dinner last night.

"That's not gonna sit well with Writer boy, He's been jealous as hell since Demming turned up" Said Esposito stirring his freshly made coffee.

"Yeah definitely, You know what call it a bet" Ryan said pulling a crisp $20 bill from his pocket "...I'll stake $20 that Castle tries his measuring contest with Demming"

Esposito considered his options, The mood of the team had certainly affected by the arrival of the Robbery Detective.

"Alright your on bro"

The partners shook on it and exited the room making their way to the respective desks.

Later that afternoon Kate had departed with an invitation from a certain Robbery Detective for a sparring session down in the gym, Sat in his usual seat eyes scanned over the murder board, switching from crime scene photo to evidence photo a theory came to him.

After explained the theory to the boys who concluded this was the first solid lead they had been gifted all day, Grabbing his jacket Esposito turned to Castle as Ryan left to inform the Captain.

"Better go and grab Beckett, She'll kill us if she misses this"

Castle nodded before walking down the back stair case towards the Precinct Gym, His eyes saw the images of Kate and her supposid boyfriend locked in an intense grappling session. Castle shook his head he had his reasons for hating the handsome robbery detective one reason was the effect he had on Kate.

Jealous didn't even begin to cover it, It didn't help that for every theory or possible break in the case he came up with. She had completely ignored it and just followed Demmings counter theory as if hanging on his every word.

If it wasn't for Esposito and Ryan he would have absolutely no idea on anything about this case, Pushing open the door and stepping towards the pair as they stood apart ready to go again both breathing hard.

"Beckett we caught a lead, Espostio asked me to come and get you" He said simply not even acknowledging her opponent which didn't go unnoticed by either of them.

Kate frowned his tone was devoid of the usual happy-go-lucky demeanor he usually had "Alright give me five minutes to finish this guy off an I'll be with you" She said throwing a right hook at Demming's head.

"You going to need more than five minutes Kate" Said Demming in response

Castle took up position against the wall and folded his arms observing the pair as they battled, Five minutes passed with no clear winner soon enough Espostio and Ryan entered wondering what the hold up was.

"I tried guys but Xena and Fabio over their wouldn't stop until someone wins" Castle sniped pointing in the directions of the mat.

Kate frowned at the attitude Castle was displaying but said nothing, Demming on the other hand took absolute exception and stepped off the mat and strode towards Castle.

"You got a problem Writer Boy" Sneered Demming

"No not really just wondering when you were finished so we can get to work" Replied Castle a calm tone to his voice.

Demming smirked it was time to teach this wannabe a lesson, "You know what Castle I'll make you a deal, If you make me tap in under three minutes we'll pack up and get to work. Sound good?" Challenged Demming

"Fine, But remember you wanted this" Castle replied

Kate stepped off the mat and stood with Esposito and Ryan the latter immediately handing his parter the crisp twenty bucks from their earlier bet earning and eye roll from Kate.

Demming took his position as he was soon joined by Castle who had removed his suit and was dressed in loose shorts and a black vest, His clearly defined muscles of his chest, back and arms clear for all to see. He took a stance and curled his fingers urging Demming to attack as Ryan timed them on his wrist watch.

Demming threw a right cross which was easily blocked by Castle, Who moved inside backing up against Demmings chest his stance lowered as the heaved the Robbery Detective over his shoulder who came crashing down on the mat back first. Castle dived for the floor and immediately started to the tie Demming up with a ground and pound, Punch's, Knee's, Elbows all were employed to devastating effect as Demming was finding it difficult to respond to the heavy and incredibly fast series of blows.

Demming saw an opening and threw a punch, However Castle avoided the blow as he rolled backwards and stood to his feet. Demming too was up and charged towards the writer throwing a mid level side kick, Castle caught the attack sweeping the mans standing leg away again throwing him down to the mat hard. Again Castle employed a ground and pound never once giving his opponent an opportunity to respond.

On the sidelines the trio of homicide detectives were shocked beyond words, They never once thought the mild mannered writer was a fighter of this calibre. Kate the most astounded at most she considered herself an accomplished fighter and even she had issues in dealing with the taller robbery Detective but Castle looked like he was toying with him.

"Dude, I never seen anyone fight like this before" Questions Ryan looking at his shocked partner

"I know Bro"

Back on the mat Demming had managed to throw Castle off him as he stood to his feet, Putting some distance between himself and Castle who was staring at him like a hunter stalking it's prey.

"Ryan what's the count" Asked Castle

"2 Minutes 30 Seconds" Came the reply

Castle then advanced and deftly avoided a right cross from Demming, As Castle pushed his opponents head down the attacking arm locked between his legs as he hopped up onto Demmings shoulders. Through the use of gravity and momentum spun around his body and both tumbled towards the ground Demming was thrown down hard, As Castle exerted maximum force onto the trapped arm locking it in an arm bar.

Demming immediately tapped as Castle released him as Ryan stopped time.

"2 Minutes 45 Seconds"

Castle stood to his feet and stomped over to his belongings as she got himself redressed "You know what, I'll let you guys handle this you all seem to done OK without me" Castle said striding out of the gym leaving behind three shocked detectives and one very surprised partner.

"That was some show Dude" Said Ryan

"You telling me, I'm definitely asking for a spar next time" Replied Esposito

The partners smiled at Beckett before exiting themselves.

Meanwhile Beckett hauled Demming to his feet "What the hell is his problem" Demming grumbled rotating his sore arm.

"I'm not sure" Replied Kate a sad tone to her voice, But some part of her knew the reason and she could only hang her head. She had done the one thing that she had always been told never do as a Cop

Abandon your partner, She had to fix this.

Hi guys

This isn't the end of this story, I've already decided to make this a two shot.

But let me know what you think, you all know what to do by now

Let me know

Knight Rider Alpha.