Title: The Theory of Inevitability
Series: The Newsroom
Pairing: Will/Mackenzie
Rating: T
Summary: Of all the things MacKenzie has said this week – and, good Lord, have there been a lot of things – the one that he keeps coming back to is wasting time. / Post-S1, with speculation on casting news that makes me nervous.

Of all the things MacKenzie has said this week – and, good Lord, have there been a lot of things – the one that he keeps coming back to is wasting time.

"Do you want to end up like me and him? Wasting time and now he's practically dead?" she'd said. It was mean, to Will and to Jim, but he had to wonder if she had a point.

He wonders about a lot of things.

"Wasting time" implies that something is inevitable, and you are just needlessly postponing it. That all they are doing now is spending the time they could be spending together apart. That, later, they'll just be able to look back at these years and laugh at how silly they were, how much time they wasted. He finds it infuriating and presumptuous and just Classic Mac and … what if she's right?

When he ponders this with Dr. Habib, the young doctor just smirks – God, he hates that smirk – and asks, "Do you think you and MacKenzie are an inevitability?"

He does feel (increasingly so) that push will eventually come to shove, that one day they'll lay all their cards on the table. But he has no way of knowing if they'll both be in the same place on that day, or if it will just happen as the result of one of them pushing the other to their breaking point, turn into a screaming match, and end badly. If that happens, and everything implodes on itself, the only time wasted will be basically the last seven years of knowing her.

Instead of this, his response is a quick, "No, of course not."

But he can't shake it. For the last four years, he's been able to sleep at night with the knowledge that she ruined them, she's the reason they're not together, she she she. But now? Who's stopping them now? Sometimes MacKenzie looks at him with such hope in her eyes, like she thinks that he might, at any moment, fall into her arms.

Like tonight. They're celebrating News Night's ratings rebound in the office, and when he pulls her into his office for a quiet toast with her favorite gin – which he keeps in a desk drawer next to his favorite scotch – he can tell that she's waiting for him.

"We're going to have to change the promos," she says excitedly, smiling as they clink glasses.

"To what? 'Not quite as bad as we used to be'?"

"I don't know. I'll figure it out tomorrow. Right now, it just feels like … It feels like …" She stumbles for words, moving her arms as the gin sloshes dangerously in her glass.

"Validation?"

"Yes!" she says, pointing at him emphatically. "Validation. Also, pride and happiness and just a little bit of revenge."

"I feel that way, too."

"Are you … feeling anything else right now?" she murmurs, biting her lip. She's looking up at him expectantly, and he can hear the wall clock ticking seconds away as he considers his response.

"Hunger," he says finally. "I'm starving."

He doesn't miss the way her face falls, or the way she immediately collects herself and moves on.

Yes, MacKenzie is waiting, but she seems all too patient.

There is dancing and champagne at the Correspondents' Dinner, and there is MacKenzie. She is loose and laughing and so beautiful, and when he takes her hand in a silent request for a dance, she accepts it and lets him lead.

They don't say much of anything as they dance around the floor to something slow and jazzy, concentrating on the rhythm and on each other. He holds her at an appropriate distance, considering that the president is in the room, but not far enough away from him that he doesn't remember how good this feels.

A new song begins, and the tempo picks up. Without missing a beat, he quickens their pace in time to the music, spinning her and dipping her and, always always, bringing her back into his arms. Mac just laughs and smiles and follows so perfectly. And when he pulls her closer as they lose their breath, she loops an arm over his shoulder and curls her fingers around his neck, and he just loves her.

He looks into her eyes and he must do it in some special way, because he sees surprise in her eyes and, again, that hope. He knows she thinks he's going to kiss her, and he doesn't know if he will. He wonders how long she'll be patient, if her conviction that this is inevitable will last forever, or if she'll grow tired of the theory and move on.

He settles his chin near her shoulder and whispers one word into her ear: "Soon."

He asks Dr. Habib to speed up his process.

"I'm ready to be healed, Doc. I'm ready to be done with the waiting and the fighting and the bullshit…"

"That's great!"

"…but I'm still not convinced she won't pull the rug out from under me again."

"What I'm hearing you say is that you want to be with MacKenzie, but you can't trust her yet."

Will waves a hand dismissively. "Whatever. Can you get me past that part?"

"Only you can get you past that part."

"Dammit."

"What?"

"I just … I miss the days when loving her was enough."

He shrugs sadly, again questioning MacKenzie's Theory of Inevitability. The thought of not moving past this for MacKenzie – with MacKenzie, for them – is a dark one. But when the wound is still festering inside of him as fresh as it was the day he threw a box of her clothes and books and hair products down the garbage chute, he's honestly not sure he'll ever be able to move past it.

Will meets a woman by accident.

She's the network's lawyer and she barges into the newsroom with the fire of ten men, asking questions and taking informal depositions and being a real pain in the ass all the while. Rebecca Halliday is everything MacKenzie isn't – calculated and deliberate and chilly. She is also direct. And when she asks Will to have a drink with her, he obliges. Because maybe it's time to move on.

For MacKenzie, this feels different. Sure, seeing him drag a parade of skanks in and out of the newsroom in the early days felt like a million tiny pinpricks in her skin, but this, watching him pursue and be pursued by one woman, a woman so antithetical of what she thought Will wanted – it's like one knife plunging deeper and deeper.

She sees them leave together and wonders if he is taking her home. Is he kissing her? Is he having sex with her? Is he making love to her? Is he buying her presents? She sits at a bar with Sloan and thinks maybe it's time to move on – but as soon as she's almost convinced herself, she remembers his hoarse promise at the Correspondent's Dinner. It had felt so honest, not like the fuckery they put each other through before, and she had believed him. She had allowed herself to lay in bed and imagine that soon, he'd be here, too. She had allowed herself to imagine that dance was a first, not a last.

Sloan buys her another shot of tequila, because she doesn't know what to say.

For all of her wondering, MacKenzie ends up knowing immediately that Will has slept with Rebecca. He looks tired but not upset about it at the morning's pitch meeting, and he has trouble meeting her eyes, and she just knows. And he knows she knows and he knows he's hurt her, and there is a moment where they look at each other and they know exactly what the other is thinking.

They're finally even.

"Okay then," she says, as everyone takes a seat. "What have we got?"

She shuffles some papers around and he can practically see her heart breaking. And he thinks to himself … this is so much more painful than being afraid of what could be.

Will breaks things off with Rebecca as quickly as they started. Maybe it is mean, but he resolves that, if it is, it is the last mean thing he will ever do to a woman.

He shows up at MacKenzie's apartment with flowers on a Tuesday night.

She is wearing leggings and a long-sleeved ACN shirt, an old one with the network's former logo. If it's the one he thinks it is, there's a hole in the back from the time she got herself caught on the strikeplate of his bedroom door one night while they were literally running to bed.

He remembers her laugh that night, how she didn't stop giggling until long after they'd made love. And he's reminded that Mac is Mac, and there's only ever been her and them.

She looks surprised to see him standing there, and before she can say anything, he blurts out, "Mac, I'm sorry."

"You have nothing to be sorry for." Because that's what she believes – that everything leading up to this is cosmic payback for her own mistake, five years ago.

"I thought—" He cuts himself off, unsure of what to say or how to say it. But she's looking at him expectantly and he musters the words. "I thought I was getting over it. The cheating. And then I thought I wasn't getting over it. And now I'm sure I'll never get over it."

Her eyes fall. She is confused and steeling herself for the worst.

"But the thing is, even after everything..." He speeds through this next part just to get the words out of his mouth – "I know I'll never get over it completely, but I want to be with you anyway."

She snaps up to look him in the eye, and she's so surprised she can't even speak. She tries, but it just turns into wet laughter.

"Are you sure?"

"Yes."

"Are you crazy?"

"Yes."

They stand there and smile at each other for a few seconds, before she repeats—

"Are you sure?"

"Yes, Mac. I'm done fucking around and making each other miserable and missing you. Can we maybe try to make each other happy for a while?"

She looks away from him, biting her bottom lip in a half-hearted attempt to hide her smile. "How long is a while?"

He uses a finger to nudge her chin up toward his face, looking her straight in the eye, as serious as he has ever been, to answer her. "Forever."

She takes in a breath and then she just starts nodding furiously, throwing her arms around his shoulders and continuing to nod into his neck. His hands splay across her back, where he is met with confirmation that this is the shirt he left dangling on the doorframe that night, forgotten as he took her to bed topless. He puts a finger through the hole and onto her back, and it makes her squirm. She's ticklish, he remembers. The involuntary squirm pushes her just far enough away to look her in the eye again, and as he leans in for their second first kiss, he sees a little fear in her eyes – but more than anything, he sees that hope again.

The kiss is slow and deliberate, his hands coming up to her face so he can stroke his fingertips along her jawline. She moans into his mouth and he is done for.

Yes, he thinks, as he pulls her toward him, her body completely flush against his. All we've done is wasted time.

Hours later, they are lying on their sides in her bed with their legs tangled together, his arm slung over her side and her hand tucked up beneath his ear. He marvels at her existence, her beauty, his place in her life.

"Do you remember that thing you said in the hospital?" he asks. "About us wasting time?"

"A little," she admits.

"You said that we were wasting time, like us ending up was inevitable, and we were just being stupid. Do you still believe that?"

She thinks for a moment. "No. I mean, we did waste a lot of time, and we were very, very stupid. Extremely stupid, really. But if this last year has taught me anything, it's that it wasn't inevitable."

"Yeah," he murmurs, rolling onto his back to look at the ceiling.

"But I tell you what," she says, settling herself on his chest, hooking a leg between his, "I'll never take that for granted again."

He smiles, closes his eyes, and kisses the top of her head. And he knows … neither will he.

The Theory of Inevitability is proven false on Thanksgiving Day, 2013. Three and a half years after MacKenzie came back into his life, another brown-haired girl arrives on the scene. Her name is Nora, she weighs six pounds and one-half ounce, and she looks so much like Mac he wonders if he was even there.

"She yawns like you," Mac laughs tiredly, enamored with their daughter's sleepy breathing.

"Does she?" he asks, too in love with both of them to care that she's humoring him. It's not like he cares that his daughter is the clone of prettiest woman he's ever known. He sits on the edge of her hospital bed and he knows how close he came to not having this, how many random events and choices and tiny splitting molecules had to line up to get him to this moment.

It wasn't inevitable, it wasn't fate – it was decisions, and it was love.

And if one "wasted" moment had been better spent, they may not be here, stroking the precious hair on Nora McAvoy's head. So he kisses his daughter's (his daughter's!) cheek and his wife's lips and appreciates that fact. And then he stretches out beside them and gets on with the business of loving them.