A/N: New to this show, but hardcore obsessed with Mac and Riley. All episodes apply. Super angsty. Title is inspired by the song by Bastille of the same name (there's two versions, listen to both), and the lyrics are "Saturn" by Sleeping At Last, which I definitely listened to on repeat writing this. It hits in the feels.

XOX

When I Watch The World Burn All I Think About Is You

XOX

You taught me the courage

Of stars before you left

How light carries on endlessly

Even after death

With shortness of breath

You explained the infinite

How rare and beautiful

It is to even exist…

XOX

Russ left shortly after the mysterious, exploding message from Oversight, ruminating on patterns and muttering to himself as the door clicked shut behind him.

Mac grabbed his third—no, fourth?—beer of the night. He popped the cap off on the edge of the counter, taking a long pull.

Alone.

Again.

Bozer didn't spend much time in the house anymore, choosing to crash at the lab more often than not. When he wasn't at the lab he was working on his movie, and Mac knew better than to bother him.

Desi wouldn't stop calling. He could answer. He could have her come over. He could be not so alone if he wanted. Their relationship was shaky at best, dancing on its last legs. They burned hot and bright, leaving nothing but ash and emptiness in their wake. The distraction she gave him would be a welcome one despite the all-consuming despair he felt after.

Mac sighed, shaking his head at that. She would push him to talk. He didn't want to talk, for christ's sake. Didn't anyone understand that? He wanted…

He wanted things to be easy. He wanted good and bad. Black and white.

He wanted to be blissfully ignorant, again.

So focused staring at the empty wall in front of him, he didn't hear Riley come in. He'd always been attuned to her presence, but knowing she was there had amplified since she'd moved in. He didn't need to hear her, he didn't need to see she was there—he just felt her. A small beacon in the dark.

She leaned against the wall he sat against and slid down until her left side aligned with his right. Grabbing the beer from his hand, she finished it off in a few swallows, setting the empty bottle off to the side. She'd pulled her dark locks free of her ponytail, and left her jacket at the door.

They sat that way for a long while, nothing but the ticking of the clock and the cluttered silence to keep them company.

Mac broke the quiet, trying to force down the lump in his throat.

"I…" he began, tears choking his windpipe. Riley wound her her fingers through his, squeezing gently. "I killed someone today. I killed one man to save millions."

He hadn't said it out loud yet. Riley gave a near imperceptible nod of her head, facing him. Tears streamed down her cheeks, mascara tracing the path they took.

"I know. So did I."

"No, Riley. You didn't…you didn't push the button. You didn't watch…you didn't suffocate a man—a man with a family. A man who knew the second I pressed that button he was dead. A man with a wife and kids and a life…" She bit out a watery laugh, though nothing about it was funny. "No, I only wrote the code that my friend exploited and turned into a weapon. I was right there, pushing that button with you—just because I wasn't in the room doesn't make me any less culpable. Doesn't make me any less guilty."

Mac closed his eyes, massaging his forehead. "What good am I if weighing the odds is the best I can do now? We're supposed to save everybody, Riley. Remember when we did? Can't we just…go back to that?"

Riley stared ahead, thinking about Christmas seven years ago and Kai's teasing statement. The words were out of her mouth before she could stop them. "It's too late, Angus. We took the Red Pill a long time ago. There's no going back for us."

"Really? A Matrix reference?" Mac said dryly, raising an eyebrow at her. "Little cliche, don't you think?"

"Maybe, but it's appropriate," She defended gently. "Doing things for the greater good isn't easy, and we know that more than most. But, let me put this in a different perspective: we do what we do—we make the hard decisions, take on the heavy burdens, remain in the shadows so that they can have their Blue Pill existence. They get to live their lives, uninterrupted. They get to be happy nine-to-fivers with two point five kids and a mortgage. Because of us."

"And what about us? What do we get, Riles?" Mac harshly snapped, running a hand roughly through his hair. "Because I'm starting to find it hard to rationalize what I've lost because of this! My mom, my dad—they're gone! Jack isn't here anymore! My aunt's a psychopath. My entire life is a lie built on more lies—hell, even my relationships are lies! Nikki was forced to be a double agent, and Nasha was too good of a person to let stay with someone like me me, and Desi…"

He chewed his lip, wanting and not wanting to say the words that danced on the tip of his tongue. They begged to be spoken. He didn't have the courage to tell anyone else, but maybe he could tell Riley.

"She isn't right, for me," He admitted, just as he'd done in Germany before all of this happened. Riley wouldn't allow herself to hope, though. Not again. He continuously went back to Desi anyway, what was the point thinking he'd change his mind.

"I don't love her, Riley. I didn't before all of this and I don't now. I keep trying to make myself love her, though. Like, if I can force the feeling it'll stick, and things will be like they used to. Like I'll be able to reclaim some part of before." Mac glanced down at Riley's hand curled up in his. He was squeezing her fingers so hard they'd blanched, but he couldn't bring himself to loosen the painful grip. Riley breathed out a soft sigh, sending goosebumps racing down his arm. There was a sadness rooted deep within her words when she spoke, and he wanted nothing more than to ask her why it was there.

"I won't tell you that you have to let go, Mac. Whether it's letting go of Desi, or your dad's death, or any of the shit we've been through lately. And I'll certainly never tell you that you have to move on, from any of it. In an ideal world, we wouldn't have to. Just…don't let it consume you. Grief is…well, grief. You'll process it when you want, and when you're ready, I'll be here," She finished on a whisper, leaning her forehead against his. "I'm always right here."

Feeling a piece of his heart stitch itself back together with her words, he fought the sudden urge to kiss her, instead speaking.

"How do you always know what to say to keep me centered," Mac said more than asked, not really looking for an answer as the clock struck two in the morning.

"Because you always know what to say to me," She smiled tiredly, dropping her head to his shoulder. Letting her hand out of his vise-like grip, Mac shifted his arm around her back to pull her in closer. Riley wound her arms around his torso, grasping the fabric of his shirt tightly to keep him anchored to her.

He drew small circles along Riley's upper arm, basking in the strange peace that had settled over him. Nothing had been solved. Nothing was fixed. The feeling of helplessness that gripped him more often than not would take over with the light of day, and yet, right here, right now…

It should be like this.

It should feel like this.

Complete. Whole.

"Can we just…stay like this."

Riley made a sound of agreement in the back of her throat. "Least 'til Matty inevitably calls us," she answered him, a slight slur in her voice as sleep began to claim her.

"Not what I meant," Mac countered, though she didn't respond this time. His phone lit up, Desi's name flashing on the screen as it vibrated across the wood floor. "You and me, Riley…this is how it should be."

His phone went black.

"Truth is, I know why I can't love Desi—I already love you," He spoke to the woman asleep in his arms, giving in and pressing his lips to the top of her head. "I'm afraid that once I tell you, this darkness will find a way to eat you alive, and I can't…I can't lose you too."

Better to keep her at a safe distance, right? Better to be miserable. Better to let sleeping dogs lie.

Well, if the world was ending, shouldn't he at least get to enjoy some small part of it before it all came crashing down?

Once again, his screen beckoned him, demanding an answer. Mac picked up the offending device, tapping the green button and pressing the phone to his ear as his arm tightened around Riley.

"Hey, Desi. We need to talk."

XOX

Riley shifted, pulling at the covers as she turned, arms connecting with something solid. Solid and warm. Knitting her forehead at the immovable mass, awareness crept across her mind as she realized the something solid was breathing.

"You always twist this much in your sleep?" A low voice rumbled beneath her ear, humor touching the edges of the words.

Riley's eyes snapped open. Her head rested on Mac's chest, her arms and legs and his sheets a coiled mess she'd managed to weave around him, binding them together. She shrugged sheepishly, biting her lip and wincing at their situation. "It's a comfort thing."

Mac smiled, blue eyes capturing her hazel ones. "Well, you should know I was trying to be a gentleman and sleep on top of the covers but you clearly had other plans. Any idea how to unwind us?" He turned slightly, putting them face to face, their noses nearly touching.

This close, she could see how clear and vivid the ocean his eyes resembled actually were.

God, how were his eyes that blue?

An amused smile graced Mac's lips, his fingers tangling in her wild hair. "You want the scientific version?"

Riley grimaced, squeezing her eyes shut and wishing she hadn't wound herself in the covers so tightly. She had nowhere to hide. "Nope, let's just pretend I didn't say that," She muttered, still not willing to look at him.

He laughed lightly, moving his other hand to cup her jaw, running his thumb over her cheekbone and smudging away some of the long-dried tear tracks. "How about I tell you that I was wondering how I never noticed that your eyes have green and gold flecks in them, making them more hazel than brown in the sunlight," Mac said, the lightness of his tone giving way to something far more serious. "They're beautiful."

Said eyes stared wide and wondering at him, assessing the seriousness of his statement. He moved impossibly closer, his forehead connecting with hers like they had last night. The air felt charged and heavy and teased possibilities she wasn't sure he was willing to give in his state. The last thing she wanted was for him to hurt her, unintentional as it may be. She needed answers, or she needed to stop this before it started. Whatever this was.

"Mac…what's happening here?" Riley whispered, a warning coating her suddenly wary tone as she placed her palm on his chest to halt him. "Because I can't be a distraction for you. That's not fair."

You'll break me, in ways that no one will ever fix.

Mac could see the fear and hurt begin to etch itself across her pretty face. Fear that she was just another distraction. Fear that she was some kind of placeholder. Fear that this sudden change was brought on by grief and sorrow and had nothing to do with love or friendship or her.

Mac swallowed hard, not daring to break their gaze as he spoke. This was either going to be the end of them, or…

"I'd never do that to you, Riles," He answered brokenly but not accusing. She had every right to assume the worst right now. If the roles were reversed, he certainly would. Relief glimmered in her eyes, and he took that as encouragement. "I've had my fair share of distractions. You…you're not that. You never could be, Riley. You're my friend, and my center, and you've been there for me in ways I'll never be able to thank you for, as long as I live. And god, I love you for that."

He brushed new tears away with his thumbs as her breath caught in her chest. "Maybe that's why I never put it together before, this feeling. Or, more like I did, and didn't want to ruin us," Mac continued, sighing heavily at the sheer emotional toll it cost to carry on. "The last few weeks—or days, really—have taught me I can't expect there to be a chance to say what I want to say. So if the world manages to end tomorrow, I want at least one honest day with you."

Riley nodded, her vision blurring from her tears. She couldn't stop the question that had invaded her mind. "What about…"

"Desi?" He finished for her, smiling fondly. "Well, she wasn't actually surprised when I ended it. Or when I told her why. Apparently she's known for awhile, and called me a stupid myopic idiot for it, which seemed horribly redundant on her part."

Riley raised an eyebrow, then shrugged her shoulder in agreement with Desi. "I mean, she's not wrong…"

"Well, I take back everything I said then," Mac smirked playfully, moving to lean on his forearm, hovering above her.

"Yeah, that's not how this works, Angus," Riley threw back breathlessly, fisting his shirt in her hands and pulling him in.

Searching her eyes briefly for any hesitation, for any other warning, he tilted her chin up, pressing his lips against hers. It was brief, a test, a taste. But it held so much promise as he pulled back, gauging where they were at.

How had he lived without this feeling?

The same question was mirrored on her face, reflected back at him.

"What happens when the world doesn't end tomorrow?" Riley asked, her gaze jumping from his eyes to his lips and back, her hands traveling down his chest, toying with he edges of his shirt.

"Then I guess I get to spend another day with the woman I'm in love with," He answered simply.

Riley nodded, biting her lip to keep from crying once more. "I love you too, Mac," She barely managed to say before his lips were on hers again, this time sure and urgent and saying everything words couldn't even try to explain.

They'd lost so much since they'd walked back into each others lives.

He promised himself right then—as lips and teeth and tongues clashed hungrily, clothes were lost to the floor, and soft sighs filled the air—that he would never lose her.

It simply wasn't an option.

The world ending?

That wasn't an option either.

Not anymore.

XOX

I'd give anything to hear

You say it one more time

That the universe was made

Just to be seen by my eyes

With shortness of breath

I'll explain the infinite

How rare and beautiful

It truly is that we exist

XOX