Note: This fic sort of came out of nowhere after watching 'This Means War' with my husband. At one point my husband thought Tuck and FDR were brothers due to the conversation at Nana's party about great grand children. And it got me thinking. That and the fact that I don't like Katie with Tuck at the end. There is something about her that bugs me.

This was going to be a oneshot but there is just too much to get out all in one go.

Updated 25/11/14, 6/12/14

The Other Agent Foster

Chapter 1- The Engagement Party

The first time that Lauren met her sister-in-law was at the engagement party that Nana threw for her and FDR. That in itself wasn't unusual. From what she heard Angelica Foster lived out of state and, like her brother, she traveled a lot. So the engagement party was the first opportunity that the two women would have to meet. But there was something off about the meeting when Lauren thought back over it later that night.

Lauren was sitting outside with FDR when a tall slim blonde woman in a white summer dress came out of the patio doors. She had a champagne glass in one hand and a purse in the other. She was looking around with a small smile on her face, a smile that you couldn't see was fake until a real smile took over. Following the mystery woman's line of sight Lauren notced that she was watching Tuck and his son Joe playing on the grass.

"That's my sister Angelica. She's a diplomatic liason with the American Embassy. Nana mentioned she might be flying in for the party."

Lauren watched as Angelica started to move towards them. Katie had joined her husband and son on the grass and the real smile on the blonde's face had slipped away once again to leave the same mask from before. But Lauren ignored the woman's reaction for the moment to ask her fiancé about her.

"Really, which one? I mean which country is she based in?"

FDR laughed in a way that Lauren was starting to recognise. It was the way he laughed when she asked something that she shouldn't, when she stumbled across something to do with his job, his real job.

"Pretty much all of them."

He answered taking a drink from the beer in his hand with a smile. His answer just confirmed her suspicions as she turned away from the approaching woman to confront him.

"She's an agent as well isn't she?"

Lauren asked with a hiss and he laughed again. That was all the answer she needed, especially when she felt someone standing behind her and a musical voice joined their conversation.

"Well, well. I have to say I'm impressed Franklin. She's pretty, and not nearly as fragile or clueless as I expected."

FDR laughed again as Lauren turned back around and he moved to hug his sister.

"Hey Angie. It's good to see you."

The real smile was there again on the blonde's face as they pulled apart and FDR introduced two of the most important women in his life to one another.

"Angie this is my fiancé Lauren Scott. Lauren this is my baby sister Angelica Foster."

The two women shook hands. Angelica lived up to her name in appearance with her flowing blonde hair and almost golden hazel eyes. She looked harmless, almost innocent but Lauren found herself wondering whether the woman was hiding a gun under her sun dress somehow or in the delicate looking purse she now had over her shoulder.

"It's a pleasure to meet you Lauren. And please don't take my teasing seriously. I was just surprised to hear that he told you what he really does for a living. Don't worry. It's a good thing."

Lauren smiled. She could have admitted that her knowledge of FDR's real career was entirely accidental, but she didn't and luckily the conversation was diverted as Tuck came over to retrieve his beer from the table behind them.

"So how are the happy couple then?"

He asked with a laugh before turning to Angelica. Addressing her in that slightly hunched way that he had of presenting himself sometimes.

"Hi Angel. How have you been?"

Now Lauren had seen Tuck shy and awkward plenty of times since they had met, but never around FDR or his family. His voice was quiet and more like the way he had spoken on their first meeting in the pub and it made her wonder.

"I'm good. How about you?"

Angelica's voice was the same but the fake smile was back as she glanced over at where Joe and Katie were sitting on the grass eating cake.

"Good, good. I'm good, we're good."

Tuck was rubbing his neck self consciously and looking down at his feet. Luckily he was saved by his son. Joe had looked up from his cake to see someone he hadn't seen in some time and ran to her with enthusiasm.

"Auntie Angie!"

The 8yr old screamed as he rushed towards the blonde woman and was swept up into her arms.

"Hey there little man. Are you having a good time?"

Joe's head bobbed up and down as he nodded. And Angelica pulled the boy more comfortably against her hip. Lauren could tell that she was trying not to look around to see where his mother was. Lauren however could see Katie clearly as she strode towards the group with murder in her eyes. Apparently so could Tuck as he put his arms out urgently to take his son from the younger Foster sibling.

"Alright Champ. How about we go and see the horses, huh? Leave Uncle Frank to catch up with his sister for a bit okay?"

With that father and son were gone and Katie was following swiftly behind them. It was obvious that Katie and Angelica didn't get on for whatever reason, but Lauren didn't have a chence to dwell on that.

"So Franklin, tell me all about how you met this lovely lady who somehow puts up with all your bullshit."

The conversation continued on for a while between the three of them and Lauren soon forgot all about the awkwardness from before. That was until she and FDR got home that night. Then she couldn't stop thinking about it.