Disclaimer: I do not own Humans or any of the characters.

There's a string of "Ooo, Mattie, you're in trouble" from her fellow backbenchers as soon as Mr. Grumpy Slouchback is finished saying, "Miss Hawkins, please meet me in my office after class."

She knows it's about the assignment, and frankly, a part of her hopes she's managed to piss him off. But he seems like the kind of ass that would fail someone out of pure resentment, and there's always the fear of ending up having to explain that to her parents. She picks up her backpack, bites back a retort, and gives him a half-hearted nod.

She surprises herself with how gently she knocks on his office door. He looks up briefly from his laptop and gestures at the seat in front of him with just a tilt of his head. She sits with her backpack in front of her- a defensive gesture she managed to discard in middle school. Well, until now that is.

"So. As you can probably guess, I was going through your assignment," he says with no emotions in his tone, something Mattie hates worse than one of his moods. "I see you've managed to find glitches in my patented software. All those awards, all those accolades, and then a first year student just takes it apart?"

She bites the inside of her cheek to dull some of the venom in her voice. "With all due respect, Sir, technology is only good as long as something better doesn't come along, and science works with people disproving other people."

He stares at her, blinking, as if he didn't expect her to say something so vaguely profound. It makes her have to resist the urge to roll her eyes. "Look, I didn't show my findings to anyone, honest. Just you. So maybe you can start working on fixing the glitches. Or just ignore it altogether. Whatever. I don't know."

He closes his eyes, hunches over in his seat and grits his teeth. "I can't ignore it. Can't turn my back on people's security."

She nods, and fidgets a little in her chair. It's still not clear why she's here. She's not being chided as she expected- this isn't how he scolds his students.

"I'd like you to work on the fix with me," he says suddenly, as if he's someone not totally incapable of reading non-verbal cues. "Although I don't know what you can do that I can't-"

"Be civil, apparently," she holds back the retort with much difficulty.

"-You were the one to point out the problem. You should be part of the solution too."

She supposes there's no point arguing with him about it. Three months back, she would have killed for a chance to work on a project with The Leo Elster. But that was before she signed up for his Intro to Tech classes, and realized just how cold and arrogant he really is. She's been waiting for the term to end ever since, and now it just got longer.

"We can work on it after your classes," he continues, "Bring your laptop. Don't be late."

She nods. "If that's all...?"

"You can go now, Miss Hawkins."

She sighs a breathe of relief when she closes the door behind her.

She's a little jumpy when she codes, and she hates to admit that it's the effect of him sitting in front of her.

"Did you try a simple binary heap first?"

She feels stupid that it didn't even occur to her, and voices that thought aloud before he can. "I'm sorry. I'm stupid."

"No, you're not," he says softly, and it's so surprising that her head jerks up in his direction of its own accord. His eyes are glued to his laptop screen as usual- he's ignoring her again- but he looks, less grumpy than usual, probably?

Mattie mentally notes to herself to wonder later if she just imagined this rare little act of kindness.

A week passes with neither of them making much progress.

"I don't even know if we need to fix this," he says one evening, slamming his laptop shut with a thud that makes her flinch a little in her seat. "I don't think others will find the glitches. Everyone isn't as smart as you."

She didn't expect a compliment from him, and she certainly didn't expect it to melt her insides. "But there's always a chance," she reasons.

He groans, resting his head on his laptop. "I'm stuck. You?"

"Same," she admits.

"Maybe we should take a break for a few days," he suggests reluctantly.

She's a little too quick to agree. "Yeah, we could use a break. I'll see you next week then?"

He looks like he's about to say something, but decides against it, and only gives her a small nod.

She's not as glad to escape as she thought she'd be.

It turns out to be a rather boring week. Her mum drags her jeans shopping for Sophie, and Harun surprises her by visiting her on campus.

She hates to admit how much she's looking forward to going back to coding with him.

"So, how was your week?" is the first thing he asks when she enters his office, and it takes her by surprise, because they've never made small talk before.

"Fine, I guess," she lies, "How was yours?"

"Fine," he parrots, and then adds just as abruptly. "So that guy you were meeting on Thursday. Is he your boyfriend?"

Mattie blinks. How did he even...? "Were you spying on me?"

He scoffs. "I was just testing the mods on my drone. You happened to be in the path of my flight."

She crosses her arms in front of her. "Either way, I don't see how that's any of your business."

"It's not-", he begins, but seems to be at a loss of words. "I'm just-" He swallows hard. "Sorry," he mumbles.

For some reason, that leaves her with this urgent need to explain herself. "For the record, he's not my boyfriend. He's just- He's just a friend."

He nods, and asks in the most casual tone he can attempt. "So you're single then?"

She can feel her cheeks inexplicably starting to burn. "I suppose."

"Here you are coding every night instead of going out," he points out. "You're a strange young woman, Matilda."

"It's Mattie," she corrects with a grin. "And I'm not gonna tell you about all the probably illegal things I do, Professor."

It's that look again, that look of wanting to say something but holding back. This time though, he forces the words out. "You can call me Leo."

It's the sincerity with which he says it that surprises Mattie the most. She bites down on her lower lip, and it doesn't help when his gaze is directed towards that action. She clears her throat. "I don't think that's appropriate."

He looks dejected for a moment, before he recoils behind his façade of not caring and hides behind his laptop screen. "Right. Sorry."

It's her turn now to struggle with whether to say the next thing. "We call you Mr. Grumpy Slouchback."

"I don't think that's appropriate," he mimics.

She grins. "It kind of is."

He huffs. "I'm not always grumpy. And I don't slouch."

"You're slouching right now."

"No, I'm not." And he doesn't even attempt to straighten up.

"Yes, you are."

"Am not," he says stubbornly, and Mattie realizes just how ridiculous this whole conversation has been.

She decides it's time to change the topic. "So you have a drone?"

He nods.

"Can I fly it sometime maybe?" she asks.

He nods again.

And then it's back to coding.

It's Friday when there's a knock on his office door, and they both look up in surprise, because he doesn't get visitors, being the loner that he is.

"Come in," Leo says, and the door half opens to reveal a brunette with long straight hair. "Mia," he mumbles, rubbing his eyes with the back of his hands. "What are you doing here?"

"You weren't answering my calls. I was worried," Mia explains briefly.

Mattie wonders if she should be here for this conversation. It never even occurred to her that he might have a girlfriend, and she's kind of surprised at how surprise isn't the dominant emotion in her chest.

She eyes the woman discretely. She's Asian. Maybe in her early thirties. And she seems nice. Everything that she isn't. Fuck, she's doing it again, she's comparing herself to this woman.

"You're not mum," Leo grumbles, breaking her train of thoughts before they lead to her derailment.

"Mum's worried too," Mia snaps back, before taking in a deep breathe and composing herself. She turns to Mattie, and extends her hand out with a smile. "Hi, I'm Mia, his sister."

"I'm Mattie. I'm a student," she says, sounding as young and vulnerable as she suddenly feels. "It's nice to meet you."

"Likewise," Mia returns, before fixing Leo with a soft glare. "At least you're working with another human being this time. Call mum. And maybe have a little fun once in a while. It won't kill you, you know."

He rolls his eyes. "This is fun. Should I call you a cab?"

"Ed drove me here," she explains briefly, and presses a kiss on the top of Leo's head. "Take care, Leo."

When she's gone, he lets out a groan. "Older sisters. Always bossing you around. Do you have any siblings, Mattie?"

"Yeah. Two younger ones," she says, amused. "Can confirm the bossing thing."

He grins sheepishly. "Well, what do you do for fun?"

"I hack into the Pentagon," she manages to say with a straight face.

His expression is a mix of mortification and pride, and it makes her laugh. "That was a joke, Leo."

She says his name before she can register she's saying it, and it's too late to take it back now. Not that she wants to. Not when it earns her that brilliant smile from him.

"You were not in class today," he states when she joins him that Monday evening.

"You noticed," she answers cheekily.

"Everything okay?"

"Uh huh," she answers with a non-chalance that she has mastered through her teenage years.

He doesn't avert his gaze from her. "So you had nothing to do with the sprinklers going off in Professor Hobbs' office this afternoon?"

"I don't know what you're talking about," she lies smoothly.

"That was a damn good prank, I'll admit," he praises her before the concern takes over. "But you're sure you covered your tracks?"

She pouts. "I did everything right, I promise."

"I know. I believe you," he assures quickly, and quirks up an eyebrow. "I'm just curious. What did he do to you?"

Mattie shrugs, trying to play it off as if it's not a big deal. "He stole one of your research papers. As much of an ass as you are-"

"-Gee, thanks!"

"-He's still a bigger ass. He deserved it."

He has to agree with that. "I'm touched. I should thank you. Ice cream?"

Coming from his mouth, that suggestion ends up sounding condescending. "I'm not a kid," she says, not amused.

"Who says ice cream's just for kids?" he bites back.

"It's for kids and the accompanying adult."

He sighs. He's not the only one who can be moody sometimes. "You know what I meant, Mats."

"Beer," she declares after a moment of contemplation. "You're buying."

He eyes her skeptically. "Should you be getting drunk on a school day?"

She fakes a gasp. Now that they are kind of sort of friends, her sarcasm is starting to break through. "I didn't know you could get drunk from beer."

With just an eye roll, he surrenders.

It's the next Tuesday when her mum shows up at his office. "Kill me now," she grumbles, wishing the ground would swallow her.

"Hi, I'm Matilda's mother," Laura introduces herself. "She tells me she's been staying late working on some project with you? I just wanted to make sure everything was okay?"

"You could have just emailed," Mattie snaps.

"I did. He didn't respond."

"Well, he's busy," Mattie snaps again, vowing not to talk to her mother, like, ever.

"I'm so sorry, Mrs. Hawkins. I'm a little behind on my emails," Leo says with a smile, going as far as standing up in his seat to shake her hand, which makes Mattie raise an eyebrow. "Mattie has been helping me code. I hope I'm not keeping her from other assignments?"

"No, no, it's fine," Laura assures quickly. "I was just worried she might be into some-" on seeing the glare on her daughter's face, she settles for the word "-stuff."

"I completely understand," Leo assures, and even offers her a tea or a coffee.

Mattie keeps staring at him after her mother's gone.

"What?" he asks, irritated.

"When did you go to charm school?"

"Oh, so, being nice to your mother is a crime now?"

"For me it is," she replies with a shrug, and voices the epiphany she's just had. "You are one mysterious dude, Leo."

And I'm trying to get to know you, this she leaves unsaid.