A/N - This is my first story for The Martian, but I'm in love with the book (especially these two) and perhaps overly excited to see the film tomorrow so this idea stuck with me. I hope you enjoy it and any feedback is appreciated :)

Disclaimer: I don't own The Martian. Unfortunate but true.

Beth hasn't told him yet.

It's something that bugs her constantly on their return from Mars (second time around and with all crew members on-board this time, thank god) even though she knows it's a silly thing to get caught up in. Chris tells her all the time, always smiles when she blushes and hides her own smile behind her hands, and he doesn't seem to mind that she's too shy to say 'I love you' back. She tells him with hugs and small kisses and whispered reassurances when he's the one to wake from a nightmare. She even made a Star Wars reference in response once, and he'd laughed so much that Lewis had told him off.

She just can't bring herself to form the words yet, only she doesn't know why and it's starting to annoy her.

Their room is quiet at this time. All of the other crew members are asleep, except perhaps Watney who seems determined to avoid sleeping in the medical bunk until Chris has to force him, and her own room is quiet except for the low buzz of computers and Chris's soft breathing. He's asleep like the dead and she should be too, but she's running on caffeine and was always a night owl even back on Earth, so she types away to pass the time and tries to convince herself that she's not avoiding sleep.

The nightmares have been getting better since they recovered Watney and started the trip home. She catches Chris tossing and turning occasionally, but she doesn't force him to talk about it so long as she's allowed to keep her own demons to herself as well.

However, she can never quite tell when she closes her eyes if her sleep will be peaceful or if she'll enter the recurring dreams of being alone on Hermes, fast running out of food-packs and knowing it won't be long before she has to move onto the crew, and she'd rather let exhaustion drag her into a dreamless sleep than risk living through that again.

She knows, rationally, that that plan will never be put into place now. But she doesn't have that assurance in her dreams.

When the white computer light starts to make her eyelids feel heavy and she can feel the caffeine starting to wear off, she sighs and calls it a night, shutting everything down and moving over to her bunk. It's a cramped space – their rooms barely support the one occupant they're supposed to have, let alone the both of them – but she's small enough to fit comfortably beside Chris and huddle close to his chest. He shifts slightly at the new weight beside him and the sudden darkness of the room, but otherwise he remains fast asleep and Beth lets herself smile at the fact that he at least doesn't seem to have a care in the world tonight.

He looks younger when he sleeps. She imagines she must as well, but it's been a far longer trip than they'd anticipated and the constant work and stress of bringing Watney home has aged them all considerably (Watney most of all, she imagines). She still isn't quite used to seeing the stress fade away from Chris's face while he sleeps and she hopes it's something she'll see more of when they're back on Earth; feet planted on solid ground with proper gravity keeping them there.

There she goes again, imagining a future with him when she can't even say she loves him.

It hits her again how silly she's being, letting her shyness take this away from her, and she looks up at Chris's face again and lets herself whisper it; "I love you."

Now that they're out, the words seem to sit easily in the air and a tension feels lifted even though she knows he can't have heard her. But there, she's said it, admitted it to herself, and it's enough to let her bury her face in his chest and try to get some sleep.

When she opens her eyes again, the lights have been switched on; Lewis's subtle way of telling them that they should get their lazy selves out of bed soon. Judging by the lack of soft breathing, Chris is probably awake already, and his small laugh when she groans at the brightness hitting her tired eyes confirms it. She kicks him lazily, but the effect is lost when she looks up at him and smiles. Last night was dreamless and she feels better for it.

"We'll need to get up soon," Chris says, his voice still thick with sleep and the bags under his eyes telling her that he'd gladly drift off again as easily as she would. "I swear, when we're back on Earth, the first thing we're doing is having a lie-in."

She giggles and lets the warmth of the thought of their future on Earth wake her up a little more. There's just slightly more than a hundred days left until that happens; a tiny fraction of the time they've already been stuck on the ship. She's prepared to wait if it means she gets more time in bed, some new music to listen to, and more places to go with Chris.

Knowing she'll have to get to work soon or she will end up falling asleep on him again, she practically rolls off the bed and playfully nudges Chris's shoulder to get him to do the same. It's his turn to groan this time but he follows suit, murmuring something about checking up on Watney and making sure the man actually slept.

They'd had a problem recently with Mark discovering that Chris's music collection was mostly legendary rock bands from the 20th century, and he'd refused to listen to anything else in his waking hours in order to 'cleanse his ears of disco'. Which had led to him strolling around the ship playing air-guitar at a time he was most definitely meant to be in bed. It was funny for Beth and the rest of the crew, and probably would have been for Chris too if he wasn't at least partly responsible for the man's health.

Remembering what she did last night just as Chris pulls on a sweater and makes for the door, she lightly grabs him back by the arm and kisses him on the cheek before finally saying "I love you."

The words come to her surprisingly easily now that she refuses to keep them tucked away, and it's worth it for the bright smile that slowly forms on the doctor's face as he realises what she's said. "Don't tell anyone I said that," she adds, because she knows that a blush must be spreading across her cheeks.

He nods before kissing her on the forehead, and when he pulls away he's still wearing that smile that makes her regret not having admitted her feelings sooner.

"Don't tell anyone I liked it."