Disclaimer: I don't own The 100. Everything belongs to whoever owns them, my wishful thinking aside.

Authors Note #1: This is my first work in this fandom, so I am really just testing the waters. – Set in 1x11, just after the camera pans out after Kane found Abby and sat down beside her, holding her. Canon compliant, could be seen as a missing scene.

Warnings: Please keep in mind this story deals with the alpha/beta/omega universe, featuring alpha!Marcus and omega!abby. This particular story has minor sexual references, but considering the trope and the freaky biology, there are definitely consent issues at play. So, to be safe: dub-con due to freaky biology. Mentions heat/rut sex and morning after pills.

Ineffable

It wasn't until he had her, weak and softly-pliable against his overheated skin that it dawned on him how long it had been since his last injection. The room spun slowly on its axis, giving him something to push against as every inch that was pressed against her, prickled with awareness. He let his head slump back against the bulkhead. Feeling her move with him, burrowing close as he kept his arm firm around her - trying to remember.

Before Jaha had been shot?

Before they'd sent down the 100?

Had it really been that long?

Why hadn't medical followed up?

Maybe it didn't matter. With everything that'd happened, the explosion, his mother's death, the frozen containment cell and then this- the aftermath of the Exodus breaking free from the Ark. Maybe this was just biology rearing its watchful head out of the haze of suppressants. Thinking it was needed. As an Alpha, he supposed he couldn't exactly be blamed for it either. In fact, he was probably lucky. Biology was likely what'd gotten him this far in the first place.

Every inch of him was soaked with sweat and engine grease. Overheated and filthy. But even he could smell it. The hot curl of a mature alpha entering the beginning stages of rut. His first since- Christ. His first since he'd presented as a teenager. Since he'd woken up, tangled in his sheets and slick with sweat. Cock hard and straining against his belly – so needy and desperate that it actually hurt. Fingers wrapped so tight around the early swell of his knot that the doctors had to pry them off one by one before they injected him.

He'd been fine after a couple days of rest. Better than fine. In fact, he hadn't felt any different. But things still changed. The way people looked at him. The way they treated him. The way his Omegan friends started to scent him whenever he joined their table at the mess hall. Like they could smell something he couldn't. It'd been like he'd been altered – changed – but he was the only one that couldn't sense it. And now, experiencing what he was - even this tiny fraction of growing awareness - it felt like he'd spent the majority of his life half blinded – hobbled - muted.

Almost as if, for the first time in forty years, he was a finally looking at the world exactly as he should.

Dammit.

He closed his eyes, trying to untangle how he felt about it as the humid air slithered thickly down his throat with every inhale. Every Alpha on the Ark was on suppressants - by law. It dampened their natural aggression and kept the population in check by negating rut completely. Unlike with an Omegan heat where biology could be cheated with the use of knotting condoms or other aids, an Alpha's rut only ended one of two ways. Death or by knotting an Omega. And that almost always meant another mouth to feed.

There used to be other options. Where an Alpha could get through rut alone without with Omega if they chose to. Natural suppressants that came from the very earth their ancestors had left behind. But they had been lost along with Station 13 almost a hundred years ago. There were morning after pills of course, but they were strictly regulated. As far as he knew, only a couple dozen were left in medical storage. Meaning, what? Twenty-four? Maybe thirty-six if they were lucky? That was thirty-six little pills for over two thousand people. The numbers were brutal and the consequences when they were denied were even more so.

Pragmatic, but brutal.

Due to a growing shortage of supplies and power, the choice had been made by a previous Council to cut the fat when it came to the expenditure of non-essential resources. And what with rut suppressors already widely in use, the morning after pill had been first on the list. He liked to think it'd always their intention to reinstate production when their power issues improved. But they never did. So now, the remainder were used for emergencies only.

Privately he'd always wondered what that meant. Jaha was a Beta so the issue had been moot for more than a few years. But Diana was – or had been - an Alpha, same as him. Did 'for emergencies only' fall under the purview of the Chancellor's discretion? He couldn't remember the last time the Council had been summoned to approve its use. Though, he supposed the last time it would have been necessary was in the case of the Omega, Aurora Blake. Which, considering the circumstances, would have likely had the same outcome if her pregnancy had been discovered when it should have been, rather than sixteen years later.

Biology was a difficult thing to navigate. But the lives of the many always had to be weighed over that of the few. Every man, woman and child on the Ark knew that truth.

He blinked, trying to clear his vision as some of the others stirred beside the door, slowly dragging themselves down the hall towards help. Murmuring about the maintenance shaft and alternative exits now that the main doors had power. He wondered idly how long they'd been sitting here. Having no real concept of time save for the migration of skin against skin as one of Abby's hands curled around the high of his flank. Digging in with her nails as if to reassure herself she wasn't hallucinating.

He sympathized, remembering the lurch in his gut when he'd seen her.

It hadn't felt real.

When he'd seen her on the other side of that door, surrounded by Diana's supporters, he thought he'd never see her again. And despite forcing himself to focus on getting Jaha and the others to safety, he hadn't forgotten that feeling.

It had been more than another failure.

It had felt like more.

Gritty and sharded like pieces of broken glass slicing viciously between his teeth.

Threatening an emotion that would have brought him to his knees if he'd been lesser.

If he'd allowed himself break again.

The low hum of the Ark surrounded them. Echoing it's heartbeat through metal and flesh. Soothing and familiar. It was a lullaby they'd all grown up knowing. Now altered, likely forever. There were hitches in its beat, off-putting and wrong. He winced as the rhythm faltered for a long, breathless second before starting up again. Their home was in its death throws and he was going into rut.

Complicated.

That was what thing entire thing was.

His head lolled closer. Resting his chin against her hair - feather-light and unsure of his welcome - as he inhaled greedily. Taking her in with long, exaggerated wuffs while he still could. Wanting to memorize it. The way she smelled. The way their scents were mingling. He wanted to remember every inch of it. No matter what happened.

He knew he was fixating on it. On the 'what ifs' and 'maybes.' But he couldn't help it. He'd never had a true rut. He'd never even knotted. And that was a good thing, according to Jaha. According to every Chancellor and Council that had come before. According to him, even. To ensure the peace and well-being of a way of life that was already poised on the brink, taming their baser natures was essential.

It was the way it had to be, for all of them.

He knew that.

But he had to admit, he had no idea it could be so much more.

He could feel it, even now, even this early. Parts of himself itself he'd never used stretching out like a plant towards a growing patch of sun. He could smell her. Abby. He could smell the caramel rich sweetness of her Omegan scent. He could smell the hands that had been all over her hours before, their acrid, angry trails smeared like something foul over her clothes. He could even smell her receptiveness. How it wasn't simply weakness and exhaustion that kept her close. But something else – fledging and small – but there all the same.

Her scent had changed the moment she'd opened her eyes and recognition had sparked. And now she radiated private contentment and acceptance. Allowing him to be the one to hold her. To keep her safe. Allowing their scents to mingle in a way she would be able to smell on her skin for days afterwards.

He bared his teeth at nothing when his cock twitched at the thought. Realizing that a dark part of him was alive with it. Satisfied and ferally pleased at the idea that every Omega on the Ark would be able to smell it and know that it was him she'd chosen. That he was her Alpha. Her mate. Her-

And yeah, that feeling was new as well.

Not bad, but new. Unfamiliar.

He replayed the moment over and over. Wondering if there was some cue he'd missed. Some signal. Something pre-existing that he was only just recognizing now. Something only accessible through the grace of hindsight and everything that made an Alpha what they were, from base cells to instincts.

He stopped short when her hand feathered clumsily atop his. Reminding him suddenly of where it'd been resting until now, intimate and affirming against the crux of her knee. Reminding him of a lot of things as her cheek bumped against his collarbone. Both of them aware of it, but neither of them doing anything to pull away.

"Marcus," she breathed, turning the syllables throaty and saturated as her thigh quivered minutely under their joined hands.

That was all she had to say for him to understand.

She trusted him.

The idea permeated slowly before the realization nearly unmanned him.

It wasn't something he deserved. He knew that. But in time it might be something he could accept. He had a feeling he was already in too deep for anything else. It might be the hormones – the pheromones they were probably both pumping out by now, but he couldn't help but start thinking about it. About what happened next. About if any of this was viable outside of this moment. If this wasn't just a fluke. If he could get a suppressant booster before he was in too deep. If medical was still even there to begin with. If she might want-

She stirred again, letting go of an involuntary sound. As if sensing the conflicted turn of his thoughts. Startling himself when he answered immediately – automatically. An ingrained response to a receptive Omega in distress. Letting go of a steady purr of sound that rumbled up from somewhere deep in his chest.

She answered with a muted little keen. Something wordless that clenched like a vice in the center of his chest. Making him tighten his grip around her another half-fraction. Starting to cultivate the dangerous, impossible idea as it began to grow roots and spread. That this wasn't just biology. That it was her. Abby. And that it'd always been if he was being honest.

It was a blood sport, wanting each other.

And it probably always would be.

They were too stubborn for it to be anything else.

"I can hear you thinking," she murmured, making him smile without sight as his eyes slowly fluttered closed. Distantly aware that he was somewhere beyond exhaustion as every single muscle in his body screamed heavy and sore.

She had a point, just like always.

Maybe what happened next didn't matter.

Whatever was coming would come, but until then, they still had this.

Maybe, for now, they didn't have to go beyond this moment.

Maybe, for now, they could just be.


A/N: Thank you for reading, please let me know what you think. – This story is now complete. However, I am considering doing a sequel if there is interest in Abby's point of view and perhaps dealing with what happens next.

Reference:

- The title, "ineffable" means: "to great to be expressed in words."