Author's notes: As promised, here's the long one. Expect chapters every week or so (I don't want to promise more than once a week, but the first few chapters are done and if I don't post them, I'll keep playing with them). This is set in early season 6, but it's AU from somewhere in season 5. Oh, and yes, NASA has done two technology demonstration missions in Hawaii - the Low Density Supersonic Decelerator was launched in cooperation with the Navy in 2014 and 2015. Cool flying saucer looking thing.

As always, I'm just borrowing the characters and the setting. I promise to return them in good condition when I'm done.

Chapter 1

Detective Danny Williams looked over at the restaurant bar from the spot where the whole team sat outside, craning his head to catch a glimpse of his daughter.

"She's fine, Danno."

"She's been gone for over ten minutes, Steven. She was going to run an errand for you, I might add. Given that you are a trouble magnet, I can only assume that whatever you gave her to do has now gotten her in trouble."

Steve shook his head. "I can see her, Danny. She's fine."

Danny waved a hand. "Your definition of fine leaves something to be desired, my friend."

Steve rolled his eyes. "I'll go check on her." He started to stand, but Danny waved him back down.

"No, I got it." He looked around the table at the rest of the team. "Who needs another?" Lou waved his hand in a no, and Chin pointed at his still full bottle. Kono said, "Thanks, brah," and passed him her empty glass.

He walked to the bar, set the bottle and glass down, and gave a nod to the bartender. He looked over at the end of the bar to see his 13-year old daughter chatting animatedly with a woman sitting in the last seat. Grace had a bottle of soda in one hand, and something flat and round in the other. The woman looked to be in her early-30s, dark auburn hair twisted up in a bun low on her neck, and dressed in a suit, though the jacket hung over the back of her chair. She leaned forward, describing something to Grace using broad hand gestures carefully avoiding a glass and plate in front of her. He raised his eyebrows at the bartender, silently asking.

"There's a whole group from NASA here. Apparently the Navy is working with them on a test mission. Grace saw her NASA pin and asked if she was a rocket scientist."

Grace caught sight of her father and Danny heard her say, "You should meet my dad." He met her halfway, where Grace grabbed his hand and dragged him the rest of the few steps.

"Danno, this is Cassie. She works for NASA!" She held up a blue patch, on which Danny could see something that looked like a cross between a rocket and a flying saucer. "Look, she gave me this!"

Danny tilted his head to look at the patch, but before he could reply, Grace continued. "Cassie says that there are actually a bunch of people in Hawaii doing space stuff. She's here for almost two weeks to talk to all of them. And she says that cheerleading is really all about science and math, so I should learn about angles and momentum and Newton's laws. And she likes pizza, so you should tell her where all the best places to eat are."

Danny looked at the woman who had obviously captured his daughter's attention, and saw that she was trying to hide a grin. "Cheerleading is all about math and science?" he asked.

"Of course it is! How do you think a pyramid works? Or how you know how high or how hard to do a basket toss? And how to tell where you'll land?"

Danny nodded once. "Never thought of it like that."

Grace tugged at his hand. "Can we watch the launch when it happens?"

Danny looked at Cassie with raised eyebrows. She took her cue well. "Grace, the launch happens pretty early in the morning. And you probably won't be able to see much since the range is closed."

Grace looked determined, but nodded politely. "I'll ask my teacher if we can watch coverage of it later in the day."

"That's a great idea. If everything goes well, we should have pictures of it when it lands."

"There you go, Monkey. We'll catch the pictures of it after it lands." Danny spun Grace around with the hand still holding his. "Now, why don't you go tell Uncle Steve about science and cheerleading. He was looking for you."

"Okay, Danno. Thanks, Cassie. It was really cool to meet you." She looked at her dad. "Don't forget to tell her all the good places to go."

As she ran back outside, Danny studied Cassie. "I think you just got my kid hooked on science."

She smiled. "All part of the job." She held out a hand. "Cassandra Wallace."

Danny shook her hand. "Danny Williams." He noticed the black folder with the restaurant's name on it laying on the bar in front of her, the pen on top and a sliver of paper peeking out.

"Almost every kid gets science, they just have to find a way to connect with it. Grace told me she likes sports and cheerleading, and there really is a lot of science there. Plus," she tilted her head and shrugged, "I know astronauts."

"Which gets you all the cool points."

"Exactly!" She smiled at him, and Danny realized he did not want to go back outside to the rest of his team.

He leaned against the bar. "So NASA is actually launching something here?"

"If by launching you mean sending up a rocket-powered payload on a really big balloon, then yes." She chuckled at his bemused expression. "It's a technology development test project that we might use for future planetary exploration missions."

"Ah ha. So you really are a rocket scientist."

She laughed. "Actually, no. I'm an engineer, but right now I'm managing a program out of Headquarters in DC. It's budget and bureaucracy stuff. Mostly I talk a lot."

"Thus you knowing what to say to Grace."

"Yeah, but you've got a way cool kid there. She's fun to talk with. Reminds me of one my nieces."

Jai stopped in front of Danny, carrying a tray with two bottles and a glass on it. Balancing the tray on one arm, he picked up the black folder in front of Cassie. "Can I get you anything else, Ms. Wallace?"

"No, I'm good. Thanks." She smiled at the man behind the bar, who then turned to Danny.

"Detective Williams, you want me to take these out to your table?"

"Thanks, Jai, that'd be great. Tell my partner it's going on his tab." He turned back to Cassie, to find green eyes studying him.

"Detective?"

"Ah, yeah. I work as part of a special crime task force here in Hawaii." He gestured over his shoulder to the outdoor patio. "That's the rest of my team out there."

"So, you're telling me of all the places I could have gone tonight, I managed to find the cop bar?" She grinned at him. "My brother will be delighted." At Danny's questioning look, she continued. "He's a deputy sheriff in Virginia."

"Older brother?" She nodded, and Danny huffed a laugh. "Then he'd probably be more terrified that you found the cop bar." He put one elbow on the bar and leaned against it. "The first time I found one of my little sisters hanging around the cop bar back home, I had a fit."

"And did it stop her?" The slightly gleeful look on her face said that she already knew the answer.

Danny sighed. "No."

She laughed. "We little sisters are such pains in the ass, aren't we?"

"I'm literally halfway around the world, and still they manage to drive me crazy sometimes," Danny groused, but fondly. "Do you see your brother often?"

"Not often enough. He's about four hours south of DC, so I drive down when I can." She studied him. "You said back home. I take it Hawaii is not your native location?"

He lifted his eyebrows and pursed his lips. "Can't decide if I'm offended or pleased you didn't pick up on the accent."

She tilted her head and wrinkled her nose just a bit. "Well… I did, but I'm Southern and over-polite, so I didn't want to assume."

"Ah, well," he tapped his chest proudly, "I am New Jersey born and bred."

"All things considered, I totally understand running away to a tropical paradise." She looked at him with wide eyes and just a hint of teasing grin.

Danny shook his head like he couldn't believe what he was hearing. "Are you dissing Jersey?"

"I mean, you do have the Boss, Bon Jovi, and good pizza in your favor. On the other hand," she shrugged, "it is Jersey."

"You do understand that I can arrest you, right?"

Cassie grinned. "I'll take my chances." Danny couldn't help but smile back at her, and he leaned in a little closer. Cassie put an elbow on the bar, which turned her more towards Danny, and propped her chin on her upturned hand. "How'd you end up here, Jersey boy?"

"My ex-wife moved here with her new husband. Which would have been fine - great, even - except that my beloved kid moved here with her." He looked out to the patio, catching a glimpse of his daughter's head close to his partner's and smiling softly. He looked back to see Cassie watching him. "Yes, I am a sap when it comes to my little girl."

"You're a dad. That's a good thing." She smiled at him, but before that smile could turn into what Danny thought might have been a moment, Cassie's smile turned into a huge yawn. She covered her mouth with her hand and laughed, embarrassed. "I'm so sorry. Please don't take this as commentary on our conversation."

He nodded sagely. "You're still on east coast time, aren't you? When you did you get in?

She crinkled her eyes, counting in her head. "Four hours ago? Five? Is it still Sunday?"

"Impressive. Trying to stay awake til a reasonable time?"

"Thought it might be bad form to fall asleep at 2. Then I'd wake up at 10 p.m., and though I am a night owl, that's a bit ridiculous."

"It's 7. Go to sleep already."

She nodded slowly. "Was about to leave, until I found myself in this fascinating conversation with a Jersey cop." She hesitated. "Which, to be honest, was not what I was expecting when I came down here to get dinner and keep myself awake for another hour."

"We Jersey cops have a way of doing the unexpected." Danny joked. He tapped a finger on the bar. "Except for where we hang out off the clock. We're boring and predictable that way. You know, in case you decide to have dinner here again."

Cassie nodded seriously. "I did rather enjoy my dinner here."

"Okay, then. Maybe I'll see you again, you know, around dinner time. Possibly tomorrow. Or the next day." Danny shrugged. "You know."

She grinned, then shook her head. "Could be a late dinner. I've got this conference tomorrow - though I'm hoping to escape the mandatory fun evening social event."

"We spend a lot of time here." He tapped his chest. "Predictable."

She slid off the chair. "See you around, Detective." She tossed her jacket over her arm, waved once at Jai behind the bar, and began walking towards the door.

Danny watched her go, so he saw when she turned briefly at the door and looked back over her shoulder at him. She smiled, but even from the short distance Danny could see her forehead furrow like she was trying to figure out what had just happened, and then she was out the door.

Danny stood still for a long moment, hands stuck in his pockets. Finally, he shook his head, and slowly turned to walk back outside where he sat down quietly next to Grace.

"Where you been, partner?" Steve asked. "Grace was telling us that NASA is doing some test here."

Danny tried for his usual grumpy tone, but it didn't sound quite right to him. "They are, and with our luck, someone will try to steal the thing or blow up the launch pad before it happens."

Steve laughed. "Always looking on the bright side, Danno."

Danny waved a hand at him dismissively and continued. "There's a whole group of NASA staff here from the mainland for the launch and Grace's new friend is one of them." He wrapped an arm around his daughter. "I think she might have even convinced this one to do her math homework without complaining."

"Danno," Grace's tone of voice conveyed exactly what she thought of math homework. "Doing math for cheerleading is one thing, but if it's homework, it's not fun."

"She's got you there, Williams," Lou said.

Danny huffed a laugh. "Yes, but fun is not the point of homework, isn't that right, my darling child." Grace rolled her eyes.

"Math for cheerleading?" Kono asked. Grace nodded enthusiastically and started to tell the rest of the group about what Cassie had told her about how math and science figured into cheerleading. Danny tried not to react every time Grace mentioned Cassie, tried to hold up his end of the conversation. He talked about how much he hated math until his eighth grade algebra teacher showed him a different way to think about it.

Steve told a story about one of his professors at the Naval Academy, who made them convert imperial to metric measurements in their head while running laps to truly understand the distances. Those stories turned into more about favorite teachers and classes they hated.

The talk went on around Danny, who sat content to mostly just listen, occasionally laughing with his friends at their stories. At one point, he looked up and caught Chin studying him with a small smile. He rolled his eyes good-naturedly at his friend, and nodded him back to the conversation.