Disclaimer: I do not own anything Castle.

Prompt: Fanfic challenge to write a story involving these four items. "An "elf" meaning a person dressed as an elf, the elf on a shelf, whatever..., a ponytail holder, a can of spray snow, a blow up yard decoration".

"Hey babe," Castle said as he walked up to Kate getting out of her car. He had two coffees in his hands, one of which he offered to Kate.

She finished pulling her hair back into a ponytail and took the proffered coffee from him, "Thanks!"

Bam said the lady, thought Castle, she is playing along.

They crossed under the crime scene tape and passed Ryan who was taking the statement of an older woman. As they passed Castle heard her say, "That man destroyed my blow up Christmas decoration..."

They walked up to Lanie who was kneeling in front of the victim sprawled over the decoration.

"What have we got?" Kate asked.

"Besides the Grinch?" Castle teased. Kate smacked his arm and rolled her eyes at him but with a smile of possession.

Lanie grinned at the exchange and said, "Male, late 20's/early 30's. Stab wounds to his chest and abdomen."

"Any ID?"

"No but he is wearing a uniform for a hardware store."

"Thanks." She turned to Castle and handed him her keys, "Field trip, why don't you go warm up the car for us."

How very domestic, Castle thought, game on!

Kate watched his pretty little behind as he walked away and then turned to Lanie. "He called me 'babe' this morning!"

"Sweetie, you are the one who said the whole thing about the handcuffs last week. Just sayin'. Now, off you go, I have to get this guy back to the morgue."

"Thanks for the help," Kate said tongue in cheek.

Moments later she opened the car door and slid into the driver's seat. She leaned over and kissed Castle on the cheek, "Thanks hun, for warming up the car."

They pulled up to the hardware store where Castle, ever the gentleman, opened the door for her.

They started to make their way up to the register but Castle, also ever the child, got distracted by the Christmas decorations.

"Look there's spray snow and window markers! I have to get some!" Castle exclaimed as he grabbed the decorations.

Kate pulled him along to the register before he could get distracted again.

Kate addressed the man at the register, who was dressed in an elf costume. "Detective Kate Beckett, NYPD. We'd like to ask you a few questions. Do you know this man?" She showed him a picture of the victims face.

"Yeah, that's Pierre, Pierre Martin. He didn't show up for work today and I had to cover for him. Seriously, where is that guy? It is so busy this time of year."

"He's dead," she said bluntly. "Has there been any trouble with customers lately."

"Yeah, actually, a little old lady has been harassing him all week about her defective Christmas decorations."

Kate gave a meaningful look to Castle before turning back to the elf, "Did she look like this?" She showed him a picture of the woman that Ryan had been taking the statement from.

"Yeah, Why?"

"Thanks for your help. Here is my card if you remember anything more. Now if you can ..." and she gestured to the stuff in Castles hands.

"Sure."

Back at the precinct the boys and Kate got to work on the timeline and the preliminary paperwork. After a time of working in silence, Ryan looked up and asked, "Where's Castle?" They looked around and saw him putting the finishing touches on his masterpiece: a winter wonderland on the windows of Gates office. Kate noticed that he had also hit the windows of the break room and the mirror in the interrogation room.

"Castle!"

"One second, I am almost done."

Kate smiled, put away her paperwork and said goodbye to the boys. She grabbed Castles coat and walked over to him. She put her hand on his back and said, "Common old man let's get out of here before Gates catches you. She has warmed up to you some but this may be a little too far."

"Nah, she will love it."

The elevator pinged and they got in as Castle shrugged into his jacket.

"Wait, did you just call me old man?"

"Yup." Kate replied.

"I am not an old man."

"Sure, sure..."

"Sure, later tonight after the kids are asleep, I will prove myself to you."

"Shut the front door, this game has gone far enough, what was it supposed to be, the opposite of strangers?"

"Uh- huh, and you liiiked it."

She blushed, "Well how many years of my life have I just lost?"

"You're the one who called me an old man."

"Yeah, well, you started this game."

"I started it and I am going to finish it." He said this with great determination. He looked into her eyes, pulled her closer, and kissed her like the young man he was.

A/N: Thanks for the great number of alerts and favourites, I was floored! This is the last one I have hanging around but throw me a prompt I guess...