Linking Promises
Summary: Pinky swear: the linking of pinky fingers to seal a promise. It was such a small gesture, and it was quite childlike, but it was the most important thing for two very lonesome people living in New York City.
Disclaimer: Me owning Castle? Hahahaha oh my god that's the greatest joke I've ever heard in my life.
A/N: You can tell I really like Wednesdays huh.

The Beginning

It all started on a Wednesday. Wednesdays were always relaxing. They were always located right in the exact middle of the week where everyone is just going about in their lives. It wasn't a Tuesday, a day where people are still bitter about the coming of Monday and it wasn't a Thursday, a day where people start contemplating about Friday.

They were both out on the swings of the playground. Ever since that gunshot from the funeral went off, those old and rusty swings located in the heart of the city was always a place where they could talk. It occurred almost every week. Going everyday could not have been an option because of their unpredictable work schedule. Once situated on the swings, they both freely talked about anything they wanted to let out. He talked about his daughter and her "hormonic" adventures through her senior year in high school. She always gave him helpful advice, since she had nothing in her personal life to contribute to the conversations. Her whole life was her job, but if she knew there was something that irked her, she knew going to the swings would be an ideal place to talk about it.

And a Wednesday it was. It was a Wednesday and rain was pouring down into the demanding city. They both had free time and their workplace was not too far away. Sure, it rained, but they disregarded their mother's warnings about getting sick in the rain. After all, rain quite an amazing type of weather. Yet most certainly, the possibility of getting sick in the freezing cold rain was the central topic of their conversation.

"Are you sure this is the greatest idea?" she asked, glancing up into the sky and back towards him. She could see the little beads of rain gathering in his little streaks of hair. She could feel the cold rain falling onto her skin. "I'm not so sure I wanna get sick."

"We're just sitting peacefully on the swings while it rains," he responded with a hint of innocence and an enthusiastic push on the swing. "How can we get sick from that?"

"Well, it's obviously really cold-"

"Haven't you ever heard of the phrase 'I don't care'"?

"I'm a detective! And a human being, too. Of course I have to care!"

"Oh, Katherine Beckett, what to do, what to do…"

She rolled her eyes at his childlike demeanor. Of course, she's gotten used to it after working with it for almost four years, but she couldn't help it.

"Okay," he continued. At this point, they were getting a bit soaked from the rain, as shown in the slight outward curl of wet hair. "I will promise you that we won't get sick. And I'll pinky swear that if you do get sick, I will gladly receive all the blame."

"Pinky swear?" She seemed a bit exasperated by that statement. What is this crazy man going to do now? "Castle, are we in second grade or something? You can just promise me and it'll be fine."

"It'll be fine? I beg to differ, Miss Katherine Beckett. Pinky swears are the most important thing in the universe. If a person breaks a pinky swear, it is a to said person and all that he or she stands for."

"Here goes your lively writer's imagination again…"

"Come on, killjoy! First you don't wanna be in the rain and then you can't bring yourself to pinky swear?"

He pouted just to mess with her. She stared out towards her with a broad smile. She couldn't bring herself to look at him just yet. He was being a bit too adorable right this moment.

"Fine," she said and pulled out her pinky. Immediately, he linked his pinky with hers and with great pride and joy he announced:

"I pinky swear that you will not get sick. If you do, I will gladly take all the blame with it."

"You're having so much fun with this."

"You bet I am."

"At least it wasn't a 'cross my heart' swear. I might have punched you in the face."

"Oh, come on, priorities! Those 'cross my heart' promises have got nothing on pinky swears."

Suddenly, the phone rang, and the two were immediately pushed back into the busy lifestyle of work.

It seemed as though the introduced pinky swear was already pushed back into their minds so as to focus on the case they were working on. But at the end of the day, she sneezed a quite huge sneeze during the end of the day.

"Damn it, Castle, you promised," she joked.

"It was just a sneeze! It wasn't like a flurry of boogers just started to block up your nose."

"Okay, that's gross. I'm calling it a night. I'll see you tomorrow."

"Just wait."

And that is how it started, on a nice and rainy Wednesday. That pinky swear was such a small gesture, but it came to be one of their most important ones in the course of their partnership because once a pinky swear is engraved into your mind, you can never forget it.