Disclaimer: Nothing's mine. All characters, settings and dialogue from the show belong to David Shore and his merry band of writers and producers. This is my first foray into the House fandom, and I'm just borrowing these characters because they're so much fun to play with.

Sense Datum

I.

The first time they meet, it's inconsequential. She knows from first-time introductions that he has been working for House for about six months, and has already deduced that he is rich. Nothing else really registers, because Chase is all-business and professional during differential sessions, and quiet and impersonal otherwise. She is, of course, quite willing to reciprocate in kind.

That's how the first few weeks go, and one day they have a ten-year old patient with the oddest list of symptoms Cameron has ever seen. House jumps on the case with a profound keenness that has nothing to do with the patient and everything to do with the puzzle. Two days fly by in a frantic rush of tests and potential diagnoses. Cameron, still not completely used to seeing patients teeter on the brink of death due to an as-of-yet unknown disease and unconfirmed treatments, feverishly browses the patient files and history in an attempt to find something, anything. With a start, she realizes it is the little boy's birthday the next day.

The boy, Mark, is too weak to move, but he still smiles brightly when his parents and elder sister surround him with an iced vanilla cake. He can't have his share of the cake right then, they all know, but the ceremony counts for something. Cameron hovers just outside the ICU, watching the teary celebration with a small smile of her own. She steps inside when she notices there are no candles.

"The gift shop downstairs ran out of them," the mother explains, and Cameron hesitates. They nod their thanks when she offers to run down to the nearest store, about a block away, and fetch them some. Cameron hurries back to the Diagnostics office to grab her coat and wallet.

House is in his office, bouncing his red ball and playing with his cane, contemplating the diagnostic mystery. Chase is sitting at the table in the adjacent conference room, pouring over the charts. He looks up when she rushes in and tells him what she's doing. She asks if he wants to accompany her.

"He's not going to care if his cake had candles if he's dead," Chase replies somewhat irritably, as he turns back to the charts. Cameron suppresses a wave of irritation of her own.

"No," she says patiently, "but it's his birthday. He deserves to have a happy moment with his family, even if he is sick."

Chase shrugs, without looking up. Cameron puts her coat on and digs into her pocket to check for her wallet. She really shouldn't, she knows, because they haven't slept for two days and tempers are roused all round. She does it anyway.

"What?" she asks him. "You don't think birthdays are important? Or are you mad because you didn't get a big present on your tenth birthday and you think nobody else should?"

Chase raises his head, and his gaze is steely. "When I was ten," he says, "I got my own themed birthday party."

What a jerk, she thinks as she's rushing out, mentally tucking the observation into the back of her mind, in the folder she's named Robert Chase.

II.

Foreman joins around six months later, and this time the introductions are much more friendly. He's much more open, and eager to go head-to-head with House. Previously, Cameron felt almost stupid being so antagonistic towards a man who was right more times than she could count. Chase didn't help, because he rarely disagreed with his boss. Foreman seems the polar opposite, and it's a relief to see someone take a stance so similar to her own.

It's one of those days when they have a case so difficult it seems impossible to diagnose. It's getting late, and exhaustion has seeped into days of caffeine-fuelled wakefulness. After countless theories and innumerable tests, Cameron is at a complete loss as to what it could be. So are the others, and of course, House is not willing to admit defeat. He's tetchy and short-tempered with every living being in his vicinity, and before retreating into his office, orders them to go home.

Cameron stares helplessly at Chase and Foreman, who look back in kind. There's a moment of silence, and then Chase is standing up and closing up his copies of the charts and gathering them all together.

"What're you doing?" Cameron asks, looking at him in confusion.

"Going home," he mutters. "You heard what House said."

"He didn't mean it," Cameron replies, slightly aghast and mostly indignant. "You're just going to leave -"

"You think there's anything left to do?" Chase asks her, files stacked in one hand and the other on the door. "You think a couple of hours slaving here is going to make a difference?"

"Yes," she shoots back, glaring at him. "It might."

"Then stay," Chase says simply, and leaves. Cameron's gaze is on his profile as it moves beyond the glass walls and out of sight, then settles on Foreman. His eyebrows are raised.

"Slackers are slackers," he says dispassionately, looking back down on his charts. "They don't work any more than they have to. Come on, let's review these files again. There has to be something we missed."

Cameron glances one more time at the empty seat that previously hosted her teammate. What a jerk, she thinks, before turning her attention back to the case.

III.

She knows Chase is fretting over his mistake, so she takes deliberate steps to try and remedy the situation. Tensions are running high in the office because of the Vogler situation, and she hates that everyone around her is acting like prepubescent children trying to prevent getting caught in their act of mischief. She hates that House is playing a stupid game, and that their perspective is getting skewed. Taking a deep breath, she steps inside.

Chase is sitting at the table, slightly hunched over with his hair in his hands. She can see from afar that his eyes are unfocused, and not really looking at the new, proper angiogram laid out in front of him. She clears his throat to catch his attention.

"I talked to House," she says, walking over to him. "He told me he doesn't want to fire you."

Chase stares at her with something akin to disbelief. "And you did this why?"

For the first time, she feels uncertain. "I thought it would help to know. I knew you were worried, and I -"

She breaks off at the glare simmering in his eyes, and feels her own temper spark. "I was just trying to help," she argues, defensively.

"Well, don't," he says shortly. "I'd appreciate it if you didn't stick your nose where it doesn't belong."

Cameron folds her arms in front of her and glares back. "You don't even care that our patient could've died because of your mistake, do you? All you're worried about is whether you'll get fired."

Chase turns away from her, his countenance hard and far from denial. "Believe what you want."

"Fine, I will," she mutters, turning on her heel and stalking out of the office. What a jerk, she thinks disgustedly, resolving never to bother sticking up for him again.

IV.

It's been more than six months since it happened, and Cameron can't believe at first that anyone can hide it for so long. She prides herself on picking up subtle clues about a person's emotional state, and she refuses to believe that she completely missed this. Especially about a person she has been physically intimate with, and even with the conceding factor of her being high on meth at the time. She ponders this for a while, whether she has missed the signs because they had been hidden so well or because they'd never been there in the first place.

She corners him when they're working in the lab together, because then there's nowhere for him to run.

"I'm sorry to hear about your dad," she says quietly, looking at him from across the big white table. Chase looks up in surprise, and something shifts in his expression.

"Thank you," he mumbles, looking back down at his work. She assumes he assumes she's done, and that's why she waits before continuing.

"I heard his funeral was in Melbourne," she says, watching him carefully. Chase is avoiding her gaze, and now he turns his back on her as well. "You never took any time off to go back there."

"Are you done stating the obvious?" Chase says, and his glare is hard as he turns, even through his blue goggles. Cameron feels the slightest stirrings of sympathy within her.

"Why didn't you go?" she asks him, voice soft. "He may have not been the best, but he was still your father -"

"Yeah, you would know, wouldn't you?" Chase says. "You want the answer? I hated him, and I didn't have any reason to go. Happy now?"

Cameron is taken aback. "How can you even say that? He's dead and you're -"

"Apparently, I'm the bastard," he replies, then looks at his computer screen as a loud beep fills the air. "Positive for botulism," he mutters, and prints out the results. "I'm going to go show this to House."

By the time he's gone, every drop of sympathy within her has dried up. Jerk, she thinks, looking down at her samples and giving up.

V.

When she first hears about the punch, she's nearly a hundred percent sure it's because Chase ran to Tritter and House found out. It's after she hears about the right diagnosis – had she not seen that same flicker of realization in green eyes instead of deep blue? – and Chase's attempts to stop House from chopping the girl in half that she wonders if she should be relieved or ashamed. Both feelings mingle inside her along with an odd sense of déjà vu, because she has seen this played out before. Except it was House last time and it is Chase this time, and she can't help wonder who's next.

The latter wins when she reaches the office the next morning and catches sight of Chase. For a moment, she can do nothing but gape, because the bruise is fresh, an ugly shade of puce that looks terribly incongruous on pale, smooth skin. Chase turns away when he catches her staring, hiding behind the newspaper.

Cameron stirs her coffee and takes a sip. She's not quite sure what she's supposed to say.

"Have you, er -" she pauses as he looks up at her, "you know, gotten that checked? It looks really painful."

Chase gives her a thin, fleeting smile, though it looks more like a grimace. "I'm fine."

Cameron settles into her seat and stares at him. "You are not fine. House punched you! He was way out of line -"

"Cameron," Chase interrupts, and his voice is strangely steady. "It's fine. You don't have to go on and on about it."

She hesitates, a little bewildered. "I don't understand. You could get House fired for what he did, if you wanted. You could get his license revoked. You could -"

"Run to Tritter?" Chase asks, slanting his head slightly. "Yeah, that seems like the logical progression of things, doesn't it?"

She decides to push a little. "You really care about him that much?"

He laughs harshly, bitterly. "Believe me, this has nothing to do with him. I couldn't care less if he spends the next twenty years in jail. All I know is I'm not gonna be the one to put him there. I like my job."

It's for the first time that she considers that maybe he's not always truthful, because she can't quite bring herself to believe him.

VI.

"House fired me," Chase says, the inflection in his voice leaving the sentence hanging. Cameron stares at him, trying to process this with the added evidence of his possessions lumped together in his arms.

She hasn't contemplated the possibility of never seeing him again before, not really. She has wished for it, of course, several times in the last few weeks. But now it has turned into reality, and she knows him better now than she has ever known him, knows that no matter what she thinks of him, he still cared for his job, and for House. It is knowing this that she decides to track him down, assure him that it wasn't his fault, because if it had been her she would've wanted someone doing this too.

"It's okay, really," he says earnestly, and she can glean that he's upset but trying to get over it. "Getting this job was the best thing that's ever happened to me. Everything about it. And losing it? I guess it's…gonna be good too."

She hurries out of there as soon as she can, because the last piece of puzzle is in place and she doesn't know what to think. She thinks of all the times she found him hostile and unpleasant, and of all the times she swore to herself she would never fall for him. She thinks of the last few months, and she wonders which one was the façade speaking. Because if she's wrong then she's taking a risk and it's not a risk she's been willing to take all this time.

Until now. Cameron finds herself standing in front of his house, on pins and needles because this kind of leap requires a courage she hasn't mustered in a long time, and she isn't sure she has it anymore.

Chase opens the door, and as she loses herself in the glorious rush of that leap, she's glad she still does.

VII.

It's seeing the myriad of job applications lying around his apartment that strengthens her resolve. Some have been barely started, others close to completion save for a recommenders' list. She knows because it's been over two weeks and he hasn't really tried, which makes her think that maybe he's not really trying and maybe he doesn't want to try. Four years is a long time to entangle yourself in a rut and it's difficult to pull out as it is. She wonders if it is harder for him than most, because this is House and he's either the easiest to let go, or the hardest.

When she and Chase arrive to his place after a lovely evening, looking forward to a lovely night, she fingers the application papers collecting dust on his desk. She takes a minute to steel herself before speaking.

"I've been thinking."

Chase meets her gaze from across the room, where he's hanging his coat. "Oh really?" he teases.

"Yeah. I talked to Cuddy today -" she takes a deep breath – "and there's an opening in the ER. I got an offer from her."

His smile falters. For a moment, Cameron's sure that she has gotten it wrong. It's possible, because she's starting to believe she's been wrong in ways she couldn't imagine earlier. And in that moment she nearly blurts out, It's okay, I want to refuse. Something shifts in his eyes, though, and she stops herself in time.

"Oh, er," he swallows and turns away. "All right, I guess."

Any other time, Cameron would've taken it as a sign of disapproval. She doesn't this time, because she's pretty sure she didn't imagine the relief palpable in his voice, or the way his posture slacked as he turned. She walks over to him and smiles, and her heart swells when he smiles back.

VIII.

When her phone rings and she finds out that Chase needs a lift, she had been planning to head home in anticipation of a relaxing weekend anyway. She stops her car at the particular bar, and heads inside. The air is thick with the acrid smell of smoke and alcohol, and she has to strain her eyes to catch sight of the back of a blond head.

Chase is so drunk he can barely stand straight, and Cameron is surprised. She hooks his arm around her shoulder and leads him outside, holding him steady as they stagger back to her car. She drives them back to his apartment, because it's closer and because if it were her she would rather suffer through the horrible, inevitable hangover in her own bed.

Cameron leads him to his mismatched sofa and lets him lie down, pushing his hair off his face. She pads into the kitchen and fetches a glass of water, then kneels down before him and gently nudges him to drink it.

"I'm sorry," he says, as he gulps the water down. Cameron has never seen him so drunk before in her life.

"It's okay," she says comfortingly. "Why did you drink so much?"

"I – I dunno," he says, his voice slurring. "My dad would've hated this. He hated it when my mum drank so much. 'S why he left."

With a start, she realizes what month it is. She thinks month because Chase has never told her when his dad had died exactly, and she never dared to ask. But it's close enough, and she feels a wave of sadness and affection wash over her.

"I'm sorry," he murmurs again as she climbs on the sofa and on top of him, taking care not to hurt him. She wraps her arms around him and burrows her head in his neck.

"It's okay," she says again. "It's not your fault. He wouldn't hate you. He didn't hate you."

Chase hiccups. "Then why didn't he tell me he was dying? Why didn't he -" His breath hitches, into something that sounds suspiciously like a sob.

He falls asleep a long time later, and she holds him close to her as she ponders the answer. She wishes she knew, because it hurts her to see how much he's affected by this.

She wonders how she could've ever thought otherwise.

IX.

She looks up when he stumbles in through the door, shutting it behind him and taking a deep breath. He looks gaunt and exhausted.

"Hi," she says, looking at him curiously. "Everything alright?"

"Hey," Chase says, with a forced smile. "Yeah, yeah, I'm – just tired."

Cameron knows that there's more to it, but stays quiet for now. She's learned by now never to take things by face value, especially when it comes to him. She scoots over and pats the spot on the sofa next to her, inviting him to sit. She pretends to ignore the way he flops down next to her, or when he wraps an arm around her waist and leans into her.

When she starts kissing him, he responds eagerly at first. It's only when she's pushed him on his back and attempted to undo the buckle of his belt that he hesitates. Cameron stops and sits up, taking in the flushed features of his face and his awkward, uncomfortable expression.

"Are you going to tell me what happened?" she asks, tilting her head slightly.

"I'm sorry," Chase says, then takes a deep breath. "It's just…there was this surgery today on a nine-year old patient. There was no way she could've – she died on the operating table. We tried to restart her, but it didn't work."

She waits, and he continues. "She was – House's patient. I told him it wouldn't work, that her chances were practically negligible." He smiles bitterly. "I guess I never really did learn how to say no to him."

Cameron leans forward and places a small, chaste kiss on his lips. "Nobody knows how to say no to him. If you hadn't agreed, he'd have made Cuddy badger you into it anyway."

"I know," he says, sighing. "And I know I'm being silly. Patients die all the time -"

"Doesn't mean we get used to it," she interrupts, giving him a small smile. "And it doesn't mean we should get used to it."

He looks marginally more cheerful, but she knows it's still bothering him. Pushing herself to her feet, she pulls out some DVDs from the cupboard and gets some ice-cream from the fridge, because she knows how important it is to just forget for a while.

X.

She wakes when a particularly cold draft washes over her, and shivers. When her hand extends and meets with an equally cold, empty bed, Cameron opens her eyes.

Padding into the living room, she meets with a surprising sight. The rug in front of the artificial fireplace is hidden by a cluster of open files and patient charts, and Chase is lying on his front, one hand propping his head up on his elbow as he pours upon them. She's pretty sure she's seen those files earlier in the evening, when he had entered the apartment with them tucked under his arm and dumped them on the nearest table.

"So this is what you do when you disappear in the middle of the night," she teases as she comes up to him.

"Oh, hey," he says, rolling onto his back and looking up at her with a bright, weary smile. "Sorry, I was just working."

"Come back to bed," she says, catching his left hand and pulling him up gently. "It's too cold to work."

He scratches the back of his neck with his other hand and looks sheepishly at his files. "I guess I should. It's just, I have this surgery tomorrow and it's really tricky. I just wanted to make sure I'm prepared -"

She doesn't know how he does it. Before she even realizes it, an hour has passed as they cuddle together on the hearth with his attempts to explain to her the intricacies of the upcoming surgery, and she finally drags him to bed.

XI.

Cameron rushes back to his apartment after work, using the key he had presented to her a couple of months ago to get in and keep everything ready. Quickly making the last-minute arrangements and scribbling the note, she glances one last time at her handiwork, turns on the television and settles down on the couch to wait.

When she hears the key turning in the lock, she presses the off button on the remote and runs to hide in the hallway. She hears Chase open the door and enter the living room, hears his noise of surprise as he takes in her efforts – a bunch of streamers and balloons hanging from every wall, a huge chocolate cake sitting appealingly on the dining table, next to a gift wrapped with colourful wrapping paper and complete with a bow.

She peeks from behind the curtain and sees him walk up to the table, and pick up her note. I'm so sorry I can't make it today. Enjoy your birthday on my behalf, won't you? Love, Al. She watches as Chase stays still for a couple of seconds, then crumples the note in his hand and turns away. Removing his coat, he switches on the TV and plops down on the couch.

It's exactly what she has been expecting, and yet it still surprises her.

Cameron sneaks up on him on account of the television volume being cranked up so high, and shouts 'Surprise!' in his ear before bursting into a loud peal of laughter. She can't stop giggling when Chase tackles her onto the sofa with him, or when he tickles her until she can't breathe. She stops only when he captures her lips with his own, in a kiss so deep and fervent in intensity she has to take a few gulps of air before she can speak again.

"I'm glad you're here," Chase says. He hasn't stopped smiling since seeing her, and she smiles back.

"I know," she says, playfully straddling him and leaning down for another kiss. "Happy birthday."

Later, when they have devoured most of the cake and are curled up together on the sofa again, does Cameron attempt to bring up what she has been thinking. She trusts herself to not mess up this time, because it's been so long and she knows better now.

"Did your parents celebrate your birthday when you were a child?" she asks, meeting his eyes solemnly. A couple of months ago, his expression would have closed off, as though shuttered behind blinds. Now, it's open, warm. She doesn't know whether it's a magnitude of how far they've come along, or how much he's changed, or how much she's changed, or all of the three. All she knows is how glad she is for it.

"Lots of times," Chase replies, allowing her to snuggle close to him. "Except my dad wasn't there for most of them, and my mum usually got too drunk before the end of the night. I got great 'I'm sorry' gifts afterwards, though."

She loops one arm around his neck and draws him into a tight hug. "I'm sorry."

"Don't be," he murmurs in her hair. "You have nothing to be sorry about."

If he had told her that even a couple of weeks ago, she would've disagreed with him. Right then, however, she thinks that maybe it's pretty close to the truth after all.