This takes place in season one during "The Soldier on the Grave"

Purity

Indy's cell phone rang as she left her last class. She frowned at the screen when she saw her brother's number. He usually didn't call her this early in the day. Tuesdays and Thursdays her classes were over at eleven, and she spent the rest of the day at voice lessons and dance classes.

"Hello?"

"Indy," Seeley's voice came over the phone softly.

It was tone she barely remembered hearing him use. There was fourteen years between her and her brother. The last time she had heard that tone she had been six years old and he had just come back from Saudi Arabia. He'd spent a lot of time with her back then. She'd never understood why, and hadn't thought to ask. She was a little girl who had gotten to hang out with her much older and cooler brother, and that was all that had mattered to her at the time. But the older she became the more she learned about her brother, and the more she understood why they had spent so much time together.

"Seeley? What's wrong?" She asked with worry.

"It's um…Bones wants to exhume Charlie Kent," She could hear her brother choking up over the line.

"The Basketball player who was killed in combat?" She asked in shock.

"Yeah…"

He didn't have to say anything else. She knew why he had called. Honor. Everything with her brother came back to that word. Especially if it had to do with combat. Charlie Kent was being disgraced in her brother's eyes, and it had to be killing him.

"I'll meet you at Sid's," She told him.

"You don't have to-"

"I'm meeting you at Sid's and that's final. See you in a little while, big brother." She said sternly.

He needed her. This was the way it had always been. She didn't know why he came to her and she didn't need to know. All she needed to do was be there for him and listen.

She quickly pulled out her keys and jogged to her car.

Maybe that's why he came to her. She didn't ask for the gory details. She just wanted him to know she was there.

This drabble takes place before the others (in season one), and actually stems from the episode that gave me the idea to give Seeley a kid sister ("The Soldier on the Grave"). He just spoke with so much certainty about the reasons a soldier would have for hanging around his much younger sister that it made me wonder if he was speaking from experience. Which led to a "What if" thought, which led to the creation of Independence Booth.

Go back and watch that speech if you don't remember. It's one of my favorite Booth speeches ever.