HI! I'm back I've been MIA of a couple of months but I'm back with a new story.

This story is completely A/U it does start off with Sam being undercover and Andy as a rookie but she is seeing Luke for about three seconds in the story. She and Luke break up and she meets Sam and they have a one nighter, read on to find out more. :)

P.S Don't worry I haven't forgotten about my other stories I've just had a lot on, hopefully I can finish all three before the new season haha :)

One's mistake..

Chapter 1

"What do you want from me Luke?" Andy asked as she held her tears back. "Because seriously I don't know what you want anymore"

"I don't know either" Luke replied shaking his head as he looked down.

He looked back up at her to find her looking to her left with tears falling.

"So what do we do now?" Luke asked after several moments of silence. Andy quickly wiped the tears from her eyes as she looked over to Luke.

Andy shrugged. "I don't know Luke you tell me because this is what you want so you need to tell me"

Luke nodded. "I have my things gone by tomorrow after work"

Andy looked at him with tears falling from her eyes not caring anymore to hide them. "So that's it then?"

"Andy I'm…" Luke begun.

"Don't, don't stand there and say you're sorry because we both know you're not" Andy trembled as she walked away. Kicking herself at the fact that yet another relationship had failed except this time even after she was warned to stay clear of him she still entered the relationship and now she found herself heartbroken and alone.

Walking on the side walk in the direction of her apartment Andy continued to analyse the relationship in her head over and over where did it go wrong? When had it gone all wrong?

Andy was so cough up in her own throughs she didn't notice the man walking towards her until she all but slammed into him.

"Sorry" Andy mumbled not looking up.

"No my fault" The man replied gruffly.

"No I wasn't look where I was going" Andy replied looking up at the man.

"No damage done" He smiled softly. "Are you ok?" he asked.

"Yeah fine, sorry" She apologised again.

"Honestly its fine" He smiled again.

Andy smiled a small smile at him.

"I'm Sam by the way" Sam she holding his hand out in front of her.

Andy shook his hand "Andy"

"Nice to meet you or run into you actually" Sam chuckled.

Andy huffed out a laugh "Yeah"

"Well you look like you're in a hurry so" Sam began

"Actually no just heading home" Andy replied quickly.

"Right your favourite show must be about to start" Sam joked.

Causing Andy to laugh shaking her head.

"Did you want to get a drink?" Andy asked out of the blue

"Um" Sam replied stunned by the question.

"Sorry you probably have things to do, it was nice to meet you sorry for running into you." Andy quickly replied as she made a move to leave.

"No wait" Sam said grabbing Andy's hand "I'd like that" Sam smiled.

Andy smiled "There's a bar two blocks that way" Andy said pointing to the direction behind him. Sam nodded his head knowing exactly which bar she was referring to only having just been to that same bar before running into Andy.

"Sounds good" Sam smiled as he turned to follow her in the direction of 'The Sky Blue'.

"So is this where you really were headed?" Sam asked as they walked into the bar.

Andy laughed as she nodded taking a seat at the bar. "Yeah I really could use a drink."

"I thought you were paying since you ran into me" Sam chuckled.

"And here I thought you were a gentleman" Andy fired back.

Sam smirked at her as the barman came over and asked what they were having. Andy looked at Sam as he raised his eyebrow at her challenging her to go first. Andy caved and answered "Whisky" to say Sam was shock would be an understatement.

"What?" Andy asked raising her eyebrow at him.

"Nothing" Sam smirked.

Andy gave him a knowing smile.

"So where were you headed?" Andy asked as their drinks arrived.

"Nowhere just heading home" Sam replied.

"Hmm" Andy hummed in response as she down her drink in one go.

Sam chuckled as he watched her.

Andy cleared her throat "So what do you do for a living?"

"Uh, I work as a mechanic" Sam said slipping his drink.

Andy smirked "So you good with tools?"

Sam smirked back "Ha, yeah"

Andy bit her lips and nodded as she looked over to the bar tender asking for a refill. The bar tender placed her drink down in front of her.

"What about you? What do you do for a living?" Sam asked taking another slip from his drink.

"Nothing as exciting as being a mechanic" Andy responded with a flirt tone.

"Nothing ever is" Sam smiled back.

Andy smiled as she down her rest of her drink.

Feeling the effects of the whiskey Andy let out a breath "You want to get out of here?"

Sam finished off his drink and responded with a smile. "Let's go"

"My apartment it three blocks that way" Andy replied pointing in the direction in front of them.

Collecting her jacket she felt Sam's hand on her lower back guiding her through the people and out of the bar.

Sam nodded as he followed her towards her place.

The short walk towards her apartment was quiet either one of them needing to fill the silence. Arriving out front of the building Andy turned to Sam. "This is it" she said as she pulled open the door and began the four story walk up. Reaching her front door she pulled out her keys and unlocked the front door.

She began to remove her jacket and turn to collet Sam's. "So do you want a beer?" Andy asked.

"Uh yeah, thanks" Sam replied as he followed her over to the fridge. "It's a nice place" Sam said as he accepted the beer from Andy.

Andy nodded "I like it" she said taking a sip of her beer.

Sam placed his beer down on the bench next to him as he move over closer to Andy. He took Andy's beer off of her and placed it next to his. He then gently brushed a piece of hair off of her face. "Do you know how beautiful you are?"

Andy snorted "Is that your line" she smirked.

"No it's the truth." Sam almost whispered as he moved his hand to her cheek and move in closer until they were both breathing each other's air.

Moments passed and Andy began to get frustrated. "Would you just kiss me already" Andy smiled.

Sam's dimples appeared as he finally leant in and kissed her.

The kiss started out soft and innocent, Andy moved her hands from Sam's waist up his back to his shoulder blades pulling him closer to deepen the kiss. Sam moved his hands from Andy's neck down her neck passed her breast he then lifted her up placing her on the counter.

Pulling away they both stared at each other as Sam's hand move under Andy's shirt lifting it up and over her head. Sam then moved back in kissing her deeply until air became necessary he then began working on her neck sucking and biting under her ear causing her to moan.

As Sam's lips were busy with Andy's neck his hands began to play with her breast. Andy busied herself in trying to remove Sam's top she moved it up his back until Sam step back and pulled it over his head.

It was Andy's turn to peek at Sam's chest. He was the beautiful one his arms were big and strong. His chest was manly he defiantly worked out. Andy couldn't help but smile.

When Sam kissed her again Andy wrapped her legs around his waist as he arms wrapped around his neck.

Sam took the hint and picked her up and began carrying her to the bedroom they both laughed as same walked through her apartment knocking down a lamp and a photo frame.

"Don't worry" Andy said breathlessly as she pulled away from the kiss.

When they finally made it to the bedroom Sam gently place Andy on the bed. Andy moved up so her head was on the pillow. Sam moved up Andy's body and pulled her up so she was sitting, he then reached around Andy's back and unclasp her bra letting it fall down her arms.

Sam latched his mouth onto her petit nipples, Andy threw her head back moaning Sam's name.

Sam laid her back down and moved down her body kissing and sucking both nipples, then leaving a burning trail down her stomach until her reached her jeans, he quickly flick the button open and pulled them down Andy's body. Andy lifting her hips to help Sam out.

Sam then kissed his way back up Andy's legs nipping and biting his way up to her sex. When he reached her panties he pulled them off without a second thought.

Once all of Andy's clothes had been removed Sam took a moment drink up Andy's perfect body. "You're so beautiful"

Sam lent in and kissed her, he then once again moved down her body until he reached her sex. Sam looked up and Andy with nothing but lust in his eye and he lowered his head and began kissing and sucking her clit.

Andy's back arch causing her head to fly back in pleasure, she had never felt like this with Luke. She had barely know Sam for two hours, but here they were interacting in the most interment act two people could do and she had never felt so alive.

It didn't take long for Andy to reach her climax which Sam barely entering two fingers in her. Sam removed his fingers and licked them clean.

Sam crowed back up and kissed Andy. "Wow" She whispered.

Sam chuckled "I haven't even began yet"

Andy reached down and unbuttoned Sam's pants, she pushed both her pants and briefs down as far as she could until Sam kicked them off her then lent down to kiss her again as Andy flip them over.

Andy smirked as she look down at Sam "My turn" she whispered in his ear.

Andy began to kiss and suck her way down Sam's body. Until she reached his shaft. Andy wrapped her hand around it and began pumping he, Sam groaned as he felt Andy's lips around the tip of his shaft.

Andy began using her tongue to tease the tip she then took as much of his as she could. Sam grunted knowing that he could cum right now and this would all be over, using all the willpower he had he pulled her off of him and kissed her "As much as I was enjoying that I'd rather be inside you"

Sam flip her onto her back and kissed her "Protection?" Sam mumbled against her lips.

Andy shook her head "I'm on the pill and I'm clean you?"

"It's been a while but I'm clean" Sam said as he pushed himself on her causing Andy to moan.

"Good because I want to feel you" Andy said breathlessly as she lined Sam up.

Without any other permission Sam slid into Andy Sam paused for a moment letting Andy adjust to his size.

"You ok?" Sam asked looking into Andy's eyes.

Andy smiled and nodded "Yeah, just bigger then I'm used to"

Sam chuckled "I'll take it easy"

Andy shock her head "No I'm fine just move already"

And with that Sam began to move. It didn't take long for Andy to reach her climax grabbing for Sam and moaning his name.

"Don't stop" Andy said huskly as she came down from her high.

Sam continued adjusting Andy's leg allowing he to go deep hitting her g-spot over and over again "I'm close" Sam grunted.

"So am I, Ohh, harder Sam" Andy whimpered.

Three long trust late and they both climax together.

"That was" Andy began.

"Yeah" Sam smirked as he lent down to kiss her.

It was a little after three in the morning before either one of them slept. After another two round sleep was calling both their names. Andy curled herself around Sam with her head on his chest and her legs tangled in his, they were both content and satisfied as they both drifted of the sleep.

When Andy rolled over the next morning she fully expected to see Sam instead she found herself face to face with a note.

Andy

Last night was amazing, I'm sorry I left without saying goodbye.

But they're things that you don't know about me,

Regardless I will remember last night for the rest of my life.

Yours Sam x

Andy read the note again and couldn't help but want to cry. She kicked herself knowing how stupid she was getting drunk and sleeping with a random guy. Why was she so upset for she knew it was only a one night stand but still she couldn't help but be sadden at the fact that he didn't stay.

I hope you like it let me know, sorry for any mistakes I wrote it and posted it