A/N: A little more fluff from me this weekend in response to Cullen's Bullpen Challenge for Halloween. I've got Booth living in an apartment here, one with open stairwells where you don't have to be buzzed into the building to get to a particular door. I live in a place set up like that and it worked out nicely for this, too.

Enjoy!

Brennan pulled into the parking lot and found a space, sighing as she stepped from her vehicle. She really did have work to do, but Booth had asked her to come over, to keep him company he said. She suspected it was really because he was trying to involve her in the current pop culture phenomenon.

Just ahead of her were three small children dress up in costumes of characters she didn't recognize, trailed closely by an adult female who Brennan assumed to be the mother of at least one of the tiny monsters. They trudged up the stairs and knocked on a door, bellowing in three cheerful voices when the apartment's resident opened up.

"Trick or treat!"

She watched with amusement as the resident dropped candy bars into each child's bag with a bright smile, then followed the bouncing costumes with her eyes as they moved to the next door and repeated the ritual.

"Bones," she heard a voice call. "You better come inside before someone thinks you're a stalker or a pedophile."

Her gaze shifted from the kids to Booth smirking at her from his doorway. "No one would think that," she replied, climbing the stairs and entering his apartment. "I was merely observing the modern perversion of an ancient Celtic rite as performed by a small group of participants."

"Yeah, they're called trick-or-treaters, Bones," he told her, shaking his head and following her inside. "They're just little kids looking to get some candy." He ducked into the kitchen to grab a couple of beers, then plopped unceremoniously down onto the couch, handing a bottle to his partner as she followed suit. "And any normal person that saw you standing out there in the parking lot watching those kids would think there was something wrong with you."

She took a drink from her beer and glanced over at him. "Are you implying that I'm not normal?"

The doorbell rang and Booth rose to answer it, his lips twisting into a smile as he was serenaded with calls of "trick or treat!"

"What've we got here?" he inquired of the gaggle of small bodies at his door. "A princess…a pirate…a mermaid…and, oh cool, a baseball player! Here you go guys…" Handing out candy to the waiting bags, his smile became more of a smirk and he turned back to his guest in the living room, picking up with the conversation where they had left off. "Come on, Bones, normal? That's a loaded word when it comes to you."

"I'll have you know that I've done plenty of things that you would consider 'normal'," she shot back.

"Like what?" he countered, dropping again onto the couch. "Like trick-or-treating? I somehow don't think so."

"But I did," she replied. She smiled gently as she continued, "Russ used to take me, every year until my parents disappeared. It was something we could do together, just the two of us."

He mirrored her smile. "Sounds like some nice family time."

"It was," she remembered. "My parents would help me with my costume, but Russ always insisted on being the one to take me out on Halloween. Our neighbors thought it was sweet of him to do that—even when he was in high school—instead of going out and causing trouble with his friends, so they used to give him candy, too. He got more than I did most years…"

Seeing her smile take on a wry quality, Booth couldn't resist the urge to tease his partner. "Wait a minute…you actually dressed up for Halloween? In a real costume and everything?"

"Yes," she told him indignantly, noting the obnoxious twinkle in his eyes.

"And you were…what? A different Nobel Prize winner every year?"

Brennan threw a pillow at him. "No. I had costumes just like the rest of the kids in my neighborhood."

"Really?" he asked skeptically. "Like what?"

"One year I was Wonder Woman," she informed him proudly.

He suddenly had a vision of a present-day Brennan dressed in a star-spangled bustier and knee high boots, and had to swallow hard to force his mind back to the conversation. "Wonder Woman?"

She nodded. "Yes. She was a strong, independent woman who helped people and caught bad guys."

"I might have known," he chuckled, "that there was a rational, well thought out reason behind it."

She crossed her arms over her chest with a "humph". "So what about you? Did you dress up and go trick-or-treating when you were younger?"

The doorbell rang again and Booth winked as he stood and moved passed her. "Saved by the bell." He attended to the trick-or-treaters, making easy small talk with the accompanying parent as he handed out candy, then returned to the couch.

Brennan looked at him expectantly. "Well?"

"Well what?" he asked innocently.

"What was your best Halloween costume, Booth?" she asked sternly. "You're always telling me you can't ask something personal without giving something of yourself in return, so let's hear it."

"At least I know you listen to what I say," he laughed. "Okay, let me think…oh, I know." He smiled broadly as the memory surfaced. "When I was ten I had my heart set on being a fighter pilot when I grew up, just like my dad. But the best I could do at the time was to convince my Mom to let me be one for Halloween."

His grin grew and Brennan found herself smiling along with him.

"We used one of Dad's old flight suits, and Mom altered it as best she could to fit me." He laughed again and leaned back against the couch. "It was still five sizes too big, but I was determined to have the real thing. I used my helmet from peewee football and attached a surgical mask to the front to make it look like an oxygen mask."

She nodded knowingly. "Classic alpha male tendencies taught by an individual to his progeny…"

The doorbell rang again and, this time when Booth rose to answer it, he did so with a thankful glance skyward. "Uh, sorry there Bones…duty calls…"

She swatted him playfully as he hurried out of the room, calling after him, "I'll still be here when you come back!"

She took another swig of her beer and imagined a ten-year-old Seeley running around the house in his father's flight suit, his brown eyes large and bright, a permanent smile plastered on his face. Her lips curved into their own grin at the thought, but she pushed it away when she heard a familiar voice at the door.

Hoisting herself off the couch and stashing the beer on the kitchen counter, she peeked around the corner to see what was going on. Booth stood in the entryway, leaning against the doorframe as he spoke casually to a blond woman.

"He's right behind me, Seeley," the woman said. "He insisted I come up first and he would follow me to make sure I didn't fall."

"Did you explain to him that he's four years old and that you're supposed to take care of him, Rebecca?"

She nodded. "I tried, but you know how stubborn he is. And now he's being so protective—just like you."

Brennan smothered a giggle from the other side of her wall. What was I just saying about alpha male tendencies being taught by one generation to the next?

"Here I am!" a gleeful voice exclaimed a moment later, as its owner popped into view.

"Hey buddy!" Booth greeted his son, gathering the little boy in his arms and lifting him up for a big bear hug. "Great costume! You look just like the monkeys at the zoo!"

Parker made some noises in response that Brennan supposed were meant to be monkey communications, but she ignored the fact that the child sounded nothing like an actual monkey. Instead, she was focused on her partner, the happiness that was written all over his face, the care with which he held Parker, the love in his voice as he spoke.

And just like that, the alpha male tendencies are subjugated to the paternal instincts, she thought. Her smile softened as she watched the two interact, an animated discussion ensuing to further compare Parker's costume to the real thing. The boy grinned brightly, his eyes flashing with enthusiasm the same way his father's often did, his fur-covered head bobbing in time with his speech as he talked. Booth hung on every word.

"Some nice family time," he had said earlier.

Brennan leaned back against the wall and nodded in silent agreement, a warm feeling washing over her. That's what I like about Halloween.