So I was stuck in traffic this afternoon and this story randomly popped into my head. It was going to be a one-shot but after writing this first chapter there was so much more I wanted to explore so it's going to be a two or possibly three chapter story. I hope you enjoy. Zoe.

Birthdays had never been anything special to G Callen. To him, they were just another day. Growing up in foster care and orphanages, kids just got lost and birthdays were rarely acknowledged.

Today was Callen's 43rd birthday and he treated it no differently to any other day. He woke, went for a run, stopped for breakfast and coffee then went to work. He didn't bother to check his mail box before he left because he had never received a birthday card before and never expected to either. When he had told his partner he had never had a birthday card, Sam had been surprised and had made a point of telling him he was going to give Callen one on his next birthday. It never came, but Callen didn't mind. Sam had his own way of celebrating Callen's birthday in the form of a dinner somewhere nice, usually where they served steak. It started in their second year as partners. Their first year, Sam didn't know when Callen's birthday was and by the time he found out the date had long passed. But every year since, Sam would take Callen out for a good meal and even better wine. This year would be different though. Sam was on another 'long weekend in Mexico' and wouldn't be back until Monday. Callen knew there would be a make-up dinner when Sam returned, but if he were honest with himself, he wasn't really bothered that he wouldn't be going out on his birthday.

As Callen settled himself at his desk, the first to arrive, he spotted an envelope on his desk. It was plain white with 'Callen' written in impossibly neat handwriting across the front. Callen put his coffee and breakfast down and picked up the envelope. Just because he had never received a birthday card, that didn't mean he didn't know what one looked like; he had given plenty of cards to others and did actually go into stores where they sold them. Callen took a quick glance around to see if anyone was waiting around to see him find it, but no-one was. He turned the envelope over and after pulling a letter opener from his desk drawer, he sliced it open and pulled out the contents. It was a bright blue card with a cartoon chimp holding a bunch of coloured balloons and the words 'Happy Birthday' written in red across the top. Intrigued to see who had given him his first ever birthday card (at least that he could remember because everything before the age of five was a mystery to him) he opened the card, his eyes widening. Written in the same neat handwriting as on the envelope were six simple words; To Callen, Happy Birthday, From Nell

The expression on Callen's face could only be described as one of confusion mixed with surprise. Not because Nell knew when his birthday was. He was pretty sure she knew everyone's personal information as well as all their dirty little secrets. And he really shouldn't be surprised that she had acknowledged it. After all, she hadn't even been with OSP a week before she threw Hetty a surprise birthday party and presented her with the perfect gift. So just why was he surprised, and also touched, that she had given him a card?

As he stared at the card in his hands, he heard Kensi and Deeks arriving. He could always hear them arriving when they car-pooled because after forty minutes stuck in a car with each other they would be bickering like children. As they neared the bullpen, he closed the card and slipped it into his desk drawer, not wanting to share it just yet, if at all.

"Morning Callen." Kensi greeted him.

"Hey man." Deeks nodded.

"Kensi. Deeks." Callen nodded. He took a quick peek in the drawer while Kensi and Deeks got themselves settled, a smile tugging at his lips as he laid eyes on the cheeky chimp and balloons. He would have to say something to Nell, let her know the gesture was appreciated. Rising to his feet, he started to head towards the stairs but stopped mid-step when he saw Eric appear at the top.

"Don't whistle, we're coming." Callen called up to him. Eric sighed and turned on his heels while Callen called over to Kensi and Deeks to follow him. When all three arrived in the ops centre, Nell was busy throwing up the new case files onto the big screen. As they walked in, she smiled a hello then returned to her work. She didn't ask Callen if he had gotten the card and she didn't say anything else about it being his birthday either. It would seem that she was content for her gesture to just be between the two of them. As Eric began explaining what was going on that required the team's attention, Callen realised talking to Nell was going to have to wait until later.

'Later' turned out to be nine hours later. The team's latest case hadn't been particularly challenging but it had resulted in the agents spending pretty much the entire day in the field. Returning only at the end of the day, OSP was already closing down for the weekend. Kensi and Deeks had made swift exits, both wanting to kick start their weekend. Callen on the other hand, whilst free to leave at any moment, was waiting. He knew Eric and Nell were still finishing up and he wanted to talk to Nell before he left. So he sat himself down at his desk and while he waited, he pulled out his birthday card. Running his fingers over the card and re-reading the message on the inside over and over, Callen couldn't understand just why such a cheap piece of what was essentially paper suddenly meant so much to him. Was it that he had actually been given a birthday card? Or was it the giver of the card? He didn't know Nell all that well but he liked her – she was always surprising him with the things she said or did and he was never bored in her company.

Callen was so engrossed in his thoughts, he almost missed her leaving.

"Hey Nell, wait up." He called when he caught sight of her disappearing down the hall past the bullpen. Grabbing his bag and jacket, Callen jogged to catch up to where Nell had stopped upon hearing her name.

"You need something?" she asked.

"I just wanted to say thank you." Callen smiled. "For the card." He held it up and saw Nell smile.

"You're welcome." She nodded.

"Heading straight home?" Callen asked as they began to walk to the exit.

"Yup."

"Got big plans?" Callen probed, an idea forming in his mind.

"No. It's been a long week. I'll probably just order take-out." Nell nodded as they stepped outside into the cool night air.

"You know, Sam and I usually go out for dinner on my birthday." Callen told her casually. "But he's kinda left me hanging tonight. Instead of take-out, what do you say to joining me for a decent meal …in a restaurant?" he glanced down at Nell as they walked, waiting for her reply. He could practically see the wheels turning in her head as she thought over the offer and he briefly wondered what it was she was thinking through.

"Sure." She finally replied. "Since Sam has ditched you for a diving trip, how can I possibly say no." she glanced up and flashed him a warm smile.

"You know Sam's not really on a diving trip." Callen told her as they reached her car first.

"Oh, I know." Nell winked and opened her car door. "So where are we going birthday boy?" she asked.

"Meet me at Yamashiro's in Hollywood, say 8.30?" Callen asked, glancing at his watch to make sure he had time to go home and get changed.

"Japanese, nice. I'll see you there." She replied as she got into her mini cooper.

As Nell drove away, Callen headed to his own car. This certainly wasn't turning out to be the birthday he had expected, but when you don't actually have any expectations, only good things can happen.

Thanks for reading, I hope you leave a review.