This story was written for the Captain Swan Secret Santa on Tumblr. There's a lot of scientific jargon, but if you're not a biologist, you can pretty much ignore it and enjoy the plot, as two grad students keep stealing equipment from each other's labs.

It had begun with a note on his desk.

It seems like everyone in my lab is running Westerns, and I desperately need to run this gel; I'll return the cell ASAP! — Emma Swan

Never mind that he needed to run a gel. Or that he needed to run it now, or his whole schedule would be thrown off and he'd be stuck in the lab till almost 9pm. This infernal Emma Swan must have assumed that because there was another Western cell in the lab that it would be okay if she took one, but he needed both to run all four gels. He could still run two of them, but he could also imagine Professor Gold's response: "Mr. Jones, is there a reason you only ran half your samples?"

"Someone from the Mills lab borrowed a cell and I didn't feel like staying till 9pm," was definitely not going to be acceptable as an answer, at least not to the man who expected his grad students to work 80 hours a week and finish their degrees within five years.

It was going to be a long night. But maybe there were some experiments he could get done in the meantime.

She was about to ask Mary Margaret where the multi-channel pipette was when she spotted the note.

Hope it's all right that I borrowed your multi-channel; ours appears to be missing and I needed to plate a PCR. I figured you wouldn't mind, since you like borrowing stuff. — Killian Jones

She groaned. She'd just been to the Gold lab to return the cell she'd borrowed; no one was there and the door was locked. How was she supposed to get the damn multi-channel? And when had he even borrowed it? She'd been in since 9am this morning, so unless …

"Mary Margaret?" she called across the lab.

"Yeah?"

"Did someone borrow the multi-channel?"

"Yeah, that guy from the Gold lab. He caught me on my way out last night and I said it was fine. Why?"

"Ugh, I need it, and no one's in the damn lab right now! With a regular pipette, it's going to take me three times as long, and I'm going to have to book a later time on the equipment."

"Let me check for you," Mary Margaret said, and she heard her friend's keyboard clack and mouse click as she checked the online calendar. "Yeah, next available time today is at 4pm. If you want, you can put it in then, and I'll be around to grab your data for you and email it to you."

"You'd be saving my life," she said, perhaps a bit too dramatically. But there was no way she could stay past 5pm, and she'd promised Regina that she'd have her PCR results by tomorrow morning.

"It's no problem."

"Still, thanks." Her urge to punch Killian Jones in the face subsided. Slightly.

Next Wednesday, there was another note.

We were out of the super-strength ECL, so I borrowed a couple mLs of yours. Will return when our shipment comes in. — Emma Swan

Killian was irritated, not because it was that much of a problem. The super-strength chemiluminescent reagents weren't frequently used in their lab; even if he did need it this week (which he wouldn't), she'd taken a small volume and there was plenty left. And, as she said, she'd replace what she took when her lab received the reagents.

No … what bothered him was that she'd taken it without asking. Who had even shown her where the ECL was in the first place? It was probably David's fault; Davey had his eye on one of the other members of the Mills lab (Mary? Margaret? He could never remember the woman's name), and he'd probably given her the grand tour of the Gold lab. And she'd probably shown this Swan person. And clearly Swan felt entitled to just take whatever she needed from anyone else's lab.

He'd show her.

Excuse me, your majesty, but if you could let me know when the super-strength ECL is available, this humble grad student would appreciate its return. Oh, and I've borrowed your ingenious device for snap-freezing samples in liquid nitrogen. — Killian Jones

Emma could have screamed. She'd just stopped by his lab to bring the ECL, which had just arrived moments ago, and he hadn't even been there. She'd returned it to David, that guy Mary Margaret was crushing on, but he hadn't mentioned that his lab had borrowed anything else.

She ran back downstairs to the Gold lab, hoping that David was still there, or that Jones had returned in the past ten minutes. She needed to snap-freeze samples—that's why she'd made the damn device in the first place—and she needed to do it within the next hour, before she'd have to go teach and then go home.

David was still there, but he wasn't very helpful. "I'm sorry, I don't know where he put it." He checked around Jones' desk, and even ran down to the liquid nitrogen tank, which was communal and kept in a separate locked room, to check and see if his labmate had left the dipper there. No such luck.

"I'm sorry," he said again. "Is there some other way I can help?"

"Yeah," she replied, still feeling exasperated. "Can you fill a cryo bucket for me?" She was going to have to snap-freeze the old-fashioned way.

Stealing for the sake of stealing is pretty rude, pirate. Thanks for nearly fucking up my samples I needed to snap-freeze. Your super-strength ECL has been returned, and I'll give you back your damn cryo bucket when I have a chance. — Emma Swan

Killian snickered. He didn't need the cryo bucket anytime soon anyway. But then he caught her post script.

PS: For real, though, had to borrow both your cells for Westerns. Mary Margaret is using all of ours.

Well, he did need those! Again! He'd show her "pirate."

Well, princess, I hope you're happy. You set back my experiments again. I suppose I'll have to pass the time by plating more PCRs. You weren't going to need your multi-channel any time soon, were you? — Killian Jones

Ugh, yes she would! Thankfully, she'd told Regina she'd have her latest PCR done by the end of the week, so it would be easy to cancel her time on the equipment this afternoon and reschedule for tomorrow. But still, this was getting pretty irritating. "Princess?" What an asshole.

It's your own fault for never being around when I come by to ask to borrow things or to return them. I shouldn't be surprised; you're probably off stealing things from other people's labs and leaving rude notes. What sort of ransom should I expect for the multi-channel?

In the meantime, seriously, I needed an extra transfer cassette. — Her Royal Highness, Emma Swan

Of course she did, he groaned.

I'm a rather reasonable man/pirate; you'll find that I've returned your precious multi-channel in exchange for the cells. However, stealing additional treasure has cost you your snap-freeze device again, my princess. The ransom is, obviously, the cassette. — Captain Killian Jones

And he'd drawn a damn Jolly Roger underneath, the bastard.

"Just tell Gold," David said. "You know how much he hates Regina. He'd love to report her to the head of the department."

"I guess," Killian replied. Regina was definitely not the most popular faculty member, and her rivalry with Gold wasn't a well-kept secret in the department. But she was on his committee, and she was known for personal vendettas against grad students (or anyone, really) who crossed her. Not only that, but it was also pretty common practice for people in different labs to borrow things from each other; Killian didn't want to be responsible for ending that practice, and ruining things for everyone.

"We'll see what happens," was all he said.

"Just tell Regina," Mary Margaret said. "You know she'll tear this guy a new one."

"Probably," Emma acknowledged. Regina Mills never had any problem going into other people's labs to talk to grad students about anything: teaching assignments, grades, or research practices. But Gold famously hated when anyone interfered with his lab, and he might make things difficult for her or Regina. Besides, Emma was the one who'd started everything — she kept borrowing stuff from Killian when he wasn't around. If she tattled on him for stealing in retaliation, she'd have to explain what was causing him to retaliate in the first place. She might get in serious trouble, or worse, make it impossible for people to borrow things from other labs.

"I'll think about it," was all she said.

"No, no, no, no, no … shit!"

"What's wrong?" David asked. Killian responded by shoving a note into his face.

Well, captain, thank you for finally returning the snap-freeze device this morning. Not sure why you needed it all week — pirate activities? Who knows. Anyway, I borrowed the key to the liquid nitrogen. — Princess Emma Swan

"Are you guys doing some kind of weird role play?" David asked, concerned.

"She borrowed the damn liquid nitrogen key, and I needed to start cells today!"

"So just go to her lab and get it."

"I tried! Mary whats-her-face was there, but she doesn't know where the key is, and Emma's gone for the weekend!"

"She's already gone? But it's only 4pm. Damn, we should have joined the Mills lab — I bet she doesn't make anyone come in on weekends."

"Davey, I'm absolutely fucked if I don't get these cells started today."

"What do you need?"

"PC-12 cells. If I don't start them today … and who knows when she'll get the key back to me …"

"Relax, Killian. I have PC-12 cells in culture right now, and I'm about to split them. How many plates do you need?"

"Four plates. You're a life-saver."

"It's no problem." David patted him on the shoulder and went to get his lab coat on.

But this had to stop happening. On Monday, he was going to track down this princess and demand that she stop taking things from the lab. Or, at the very least, he was going to talk to Gold about getting an extra key for the liquid nitrogen.

Emma had to stop herself from swearing violently as soon as she reached into her pocket and pulled out the key to the liquid nitrogen instead of her house keys.

"Mom, what's wrong?" Henry asked.

"Nothing, kid," she said. "Everything's fine. Just pulled out the wrong keys." She fished back into her pocket and grabbed her house keys.

"Mom," he said again, very seriously. He was very serious for an 8-year-old, and he'd inherited her ability to tell when people were lying. Sometimes, it made it very hard to raise him properly.

"I brought something home from work that I'm not supposed to bring home," she explained, opening the door to the apartment building and following her son up the stairs to their unit. "I think I'll have to go into work tomorrow."

"But you promised we could go to the park tomorrow!"

"Henry, come on, you know how it is." Now that Emma was in grad school, and was no longer working 9-5 at a biotech company, she sometimes had to work on the weekends. Fortunately, Regina was very understanding about Emma's situation, and so she knew that sometimes, Emma just couldn't stay late or come in on a weekend. But sometimes, a project demanded a Saturday or Sunday, and Emma would find a sitter and head to work. "I just need to drop something off. I'm sure you can come with me, and then we'll go to the park."

Killian was startled by the sound of the door opening to the lab. David had already come in this morning, set up an experiment, and then left for a coffee date with his new lady friend, Mary Margaret. He chuckled; perhaps the date had gone terribly, and his friend was back already.

"Captain Jones?" someone asked, and then giggled. He turned to see a small boy, perhaps seven or eight years old, grinning as if he were referencing some elaborate inside joke. Before he could register why there was a small child in the lab, or question why this kid was calling him "captain," he realized that the boy was holding someone's hand. He looked up to find himself gazing at probably the most gorgeous woman he'd ever laid eyes on.

He didn't recognize her. Her long blonde hair was loose around her shoulders, and she wore riding boots, jeans, and a red leather jacket over a white shirt. Clearly, if she was a grad student, she wasn't here to work, not with that jacket or her hair down. But if she wasn't a grad student, who was she?

"Sorry, couldn't resist," she said.

And then it hit him: the little boy had called him "Captain Jones."

"You must be Emma Swan," he said, his mouth suddenly dry. He stood to greet her.

She smiled and held out a hand to shake his. "It's nice to actually finally meet you, Killian," she said.

"Likewise," he said, and his gaze drifted down to the little boy standing next to her. "And who might you be?"

"I'm Henry!" the boy said, dropping Emma's hand to shake Killian's. "Mom said you're a pirate."

"Oh, did she?" he asked, grinning. He returned his gaze to Emma's face; she was watching his expression carefully. "Well," he said, still looking at Emma, but speaking to Henry, "I hope she told you that, as a pirate, I'm not easily surprised." Or at least he was good at hiding his surprise — he'd never have guessed she was a mother.

She simply raised an eyebrow at him, but she smiled. "I thought you would be working today, so Henry and I decided to drop off the liquid nitrogen key on our way to the park." She pulled the relevant item from her jacket pocket and placed it in his palm. Her fingernails grazed his skin gently. "I want to apologize for taking it. Obviously, I wasn't working very hard to, uh, cease the hostilities, as it were. But I really didn't mean to take the key overnight. I was just in such a rush; I wasn't thinking and just put it in my pocket by accident."

"Well, thank you for returning it. I'm going to talk to Gold on Monday; you folks in the Mills lab clearly need your own key."

"Thanks," she said, smiling gently. "Anyway, I'm sorry for being a jerk about taking your stuff. I know how Gold is about working you guys half to death."

"Well, I have to admit, I was jealous that you were leaving so early every day, but now I can see that perhaps you're not exactly going home to relax."

"Being a single parent isn't terribly relaxing," she admitted. "Anyway, I'll let you get back to your work. Maybe I can more formally apologize over coffee some time."

"I'd like that." And he knew he really would like that.

"All right, then. Henry, ready to go?"

"Yep! Let's go, Mom." And they began to move towards the door.

"Wait!" Killian said suddenly. As Emma turned around in confusion, he began to mentally catalog the work he had to do today. He'd already dealt with the cells that David had given him, and he'd analyzed one set of PCR results. He was waiting until later in the day to deal with his latest Western blot, so that he could run the experiment overnight. And all that was left to do right now would be to analyze another set of PCR results and grade some lab reports.

And that could wait till tomorrow. "Perhaps we I could join you at the park. It's been a long morning."

"Cool, we can play pirates!" Henry said.

"You sure?" Emma asked, and he could tell that she was really asking a different question: Are you sure you want to get involved with a woman with a kid?

"Absolutely," he replied. "As long as we can also grab that coffee on the way."

"Sure," she replied.

He grabbed his jacket and keys, and hurried ahead of them to the lab door. "After you, princess," he said with a wink, opening the door for them. She rolled her eyes, but she was still smiling.

Two hours later, Henry was involved in a serious game of "pirates" with seven or eight other kids, and Emma and Killian were relaxing on a nearby bench. Emma was surprised at how quickly she and Killian had already exchanged numbers (he said it was so that they could call or text if they needed to borrow or return something, but please, she knew better), but for the first time since she had Henry, it felt exciting to be clicking with someone.

And, boy, were they clicking. They were both older grad students, having started their respective programs in their mid-twenties after working in labs for a few years. Neither one of them had much in the way of family, and because of the demanding nature of his boss and her obligations as a single parent, neither one had much time for a social life outside of the lab (or, in her case, playdates).

And she wasn't sure how Mary Margaret, who'd run into Killian more than a few times, had failed to mention that he happened to be unbelievably attractive and British. When they'd finished their coffee, he'd run off to the nearest Starbucks for more, and she'd sent some scolding texts to her friend (who didn't reply; she was on a date with that David guy).

Finally, Henry was worn out, and Killian mumbled something about how he should get back to work. Emma felt a panic that she hadn't felt in a while — the panic of wanting a great date to continue when it was clearly ending. "Henry, why don't you go say goodbye to Lilly and Mark?" she said, pointing to his friends who were all the way on the other side of the playground.

As soon as her son's back was to her, she turned, grabbed Killian's jacket by the lapels and kissed him. She thought she'd be surprising him, but true to his word, he proved difficult to surprise; his arms had come around her automatically, and he kissed her back enthusiastically. She broke the kiss after only a few moments, knowing Henry would be on his way back, but she couldn't stop smiling, and he kept his arms around her.

"Sorry I keep stealing stuff from you," she said.

He laughed. "Well, if you hadn't noticed, I'm hardly angry anymore."

His phone rang, and he cursed under his breath, letting go of her and fishing his cell phone from his jeans. "It's David."

"Guess their date is over," she said. Guess ours is, too.

"Hey, Davey," he said, answering the phone. She suddenly felt Henry's hand curling into hers, and she looked down at him and smiled. "Calm down, Davey, she returned it. Really! I was there! Hold on." Killian frowned and reached into his other pocket. A look of mild horror crossed his features as he pulled out the key to the liquid nitrogen. "Um, I'll be right there," he said sheepishly, and then hung up.

I hope you enjoyed this story, and I'd love to hear what you think!

I am no longer posting stories to FFnet. For new stories, check out my page on AO3 (same username, phiralovesloki; there's a link in my profile as well).