Summary: [SPOILERS FOR INFINITY WAR. BIG ONES.] There's a saying: Hell hath no fury like a woman scorned. Howard used to say that, but he'd add an extra piece. A woman scorned hath no rage like a Stark angered.

[Or: After everything, on a silent planet of ruins, Tony's hands shake as he stares at the dust that coats his fingers.]

AN: AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAGGGGGGGGGGGGGGGGGGGGGGGGGGGHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH (SCREAMS FOR ETERNITY)

Also, warning: SPOILERS FOR INFINITY WAR PART 1 AHEAD. No, BIG ONES, I am not kidding.

...

The planet is utterly silent, and Tony has dust on his hands.

Dust that used to be Peter.

Tony sits in his broken suit, his head between his knees, and tries to breathe. Stares unseeing at the ground, tries to parse what just happened.

His hands are shaking.

His hands are shaking, there's dust on his fingers, his breath is shuddering dangerously in his chest, and Peter (and Strange, and Quill, and the two others; the burly tattooed man and the woman with the antennae) are nothing more than particles of dust that have already started scattered in the breeze.

Fuck. Fuck. How did – fuck. It all went so wrong. They were so close. They were so close, and then all of a sudden they weren't any more, and everything was happening so fast, and then Tony was gasping around a hole in his side and Strange was giving Thanos the Time Stone (why, why, what the fuck, Strange) and Thanos was vanishing into a portal and that was that, they'd failed.

But then…

Then.

Then Peter –

Fuck. Fuck.

Fuck, the panic and the grief and the sheer scale of what they failed to stop rises like a tide, and he tries to crush it back down again (if he lets himself grieve, he'll drown, he knows it), but it's relentless and it just keeps rising.

"The Guardians' ship will be here somewhere," the blue woman says into the silence of the ruined planet, and when Tony looks up at her, her eyes are roving in short, jerking movements as she scans the terrain.

She's the only other one left. It's her – this strange woman who crashed a spaceship into Thanos halfway through the fight and who Tony doesn't even know the name of – and him, all alone on this abandoned planet. Everyone else – everyone else, fuck – they've all… They're all – . It's just the two of them.

"I will drop you on the nearest populated planet and you can barter your way back to Terra from there," she continues.

"Yeah, uh, hell no," Tony replies, and the panic and grief in his chest recedes as it's washed away with something cold and hard and violent, and yes, yes, this is what he needs his emotions to do right now – panic and grief are useless, they're not going to be any help to him whatsoever. Rage, though – rage, and righteous fury, and vengeance – that he can use.

"No," he repeats, and (Stark men are made of iron, he hears his father say) there's iron in his voice and in his spine and in his blood. "You're going after him. And if you think I'm doing anything other than coming with, then you're delusional."

The alien woman scoffs.

"You're a Terran," she says dismissively, turning away to begin her search for the ship in earnest. "He will tear you to pieces."

"Who was Gamora?" Tony asks, because he's not above punching below the belt when necessary, and he's rewarded when the blue woman snaps her gaze back to him, her expression flat and deadly and full of pain.

"Quill mentioned her as well," Tony continues. "Several times, in fact. And then she was the first thing you asked after once you came crashing in here. Who was she?"

The woman stares at him for a long time, expression unmoving.

Tony stares back; not challenging, just waiting. Several long moments pass.

"She was my sister," the blue woman eventually concedes, cutting her eyes away from Tony's.

"Ah," Tony says. "So you and I are in the same boat right now then."

The woman looks back at him, her movements unnaturally sharp.

Tony knows that she's dead, this Gamora woman. Knows Thanos killed her. It's why he brought her up. Brutal tactic, maybe, but hopefully effective.

"The kid – the one in the red suit," Tony says, and his voice wavers with grief without his permission, and he has to swallow dryly and work his jaw for a moment before he can force himself to continue. "He was – he was my… responsibility. I was supposed to look after him. Make sure he didn't, you know. Wind up in too much trouble, fall into a hole too big for him to climb out of. I was supposed to make sure he didn't get hurt."

He pauses for a second, rubs a hand over his mouth as he winces. "His aunt – shit, his aunt is… This is gonna kill her. Fuck."

Gamora's sister is watching him, unmoving and unblinking.

Tony glances down at the spot he last saw Peter – the spot where he lay, apologising of all things as he turned to dust – and his mind plays the scene out before his eyes all over again, as though he didn't just live it, as though it's not already holding the number one spot for the primary thing that's going to keep Tony awake with the weight of guilt and what ifs for the rest of his life.

His mind replays it, and he hears an echo of a wobbly Mr Stark, I don't feel so good. Sees in his mind's eye the way Peter stumbles, staggers forwards, collapses into Tony. Can feel the memory of arms wrapped around him, can feel the phantom clench of hands that aren't there any more clinging desperately to him, terrified and fading in strength. Hears I don't wanna go, I don't wanna go, please – please.

Tony clears his throat. Blinks his eyes closed in an attempt to clear his vision.

When he looks up at the woman, she's still watching him.

"The point is. That purple piece of shit killed my kid," Tony says, and the quaver in his voice is rage, this time, not restrained grief. He learnt as a child how to channel his grief and distress into anger, and while his therapist says that's not a healthy coping mechanism, it's sure as hell serving him well now.

"So I'm coming with you," he continues, voice unyielding. "And we're going to hunt this son of a bitch down. For what he did to Peter, and for what he did to Gamora. We're gonna hunt him down, and we're going to kill him. What do you say."

The alien woman stares at him for a long moment, her eyes calculating even as the rest of her face is an unnaturally blank mask of expressionlessness.

Finally, she nods – a single sharp jerk of her head.

"Very well," she says, and that's that.

There's a saying. Hell hath no fury like a woman scorned. Howard had his own version of a second part. A woman scorned hath no rage like a Stark angered. And usually Tony hates living up to Howard's sayings. But on this front, the old man is right on the money.

Because Tony plans on tearing Thanos apart with his bare hands, if he has to. They may have lost this round, but he knows what he's up against this time – knows better what he's up against, and he's already forming plans and strategies for how to defeat the asshole; how to smear him into an unrecognisable smudge of purple sludge on the ground.

"We'll start with Earth," Tony says, levering himself up and wincing at the still-healing stab wound in his side. Dr Cho's nano-flesh might be fast, but it's still gonna sting for a few hours at least while the spray-on artificial flesh knits Tony back together.

The woman twitches her gaze back to Tony.

"He will no longer be on Earth," she says, voice hard. Tony doesn't think her voice has any setting otherthan hard, come to think of it.

"No," he agrees, and casts one more look at the ground where Peter lay. There isn't even any dust for him to collect. He would collect it, if he could. Peter doesn't deserve to be left here, alone on this mausoleum of a planet. He deserves to come home. But there's nothing to bring home. The dust all blew away on the wind, before Tony had even fully computed what had just happened.

Silently, Tony makes a promise. He said it once, to Loki, all those years ago in his Tower, while the Chitauri army that Thanos sent wrought death and destruction throughout Manhattan. Time to come good on the threat.

"I promise, kid," he mutters, and then turns away. "Say, what's your name, anyway? I'm Tony," he says, picking his way over rocks and earth towards where Quill and his people had left their ship. He doesn't let himself look back.

"Nebula," the alien woman responds after a moment, and Tony can hear her following along in his wake. "And if you know he is no longer on Earth, then why bother with a journey there?"

"Because, Nebula," Tony responds, deliberately committing the name to memory. Pepper isn't here to remind him of it next time he needs it (and shit, Pepper, he's trying desperately not to think of her – of her, or Rhodey, or Happy, or Vis, any of whom might be gone, might have been caught up in the war that doubtlessly went down on earth, or might have been turned to dust, like Peter, and Tony can't think of that, he cant. He won't be able to function, if he starts worrying about who is or isn't going to be left on earth).

"For one," he says, "I need supplies. My journey here was somewhat unplanned, and I don't have half the shit with me that I would usually bring if I'm gonna face off against a giant murderous grape. Plus my suit is damaged – I've got enough nanobots left for a mask and two repulsors, and that's it, and I'm gonna need more than that. But also, Earth was the last place we know for sure that he was, and that feels like a good place to start tracking someone."

The ship comes into sight – the, what did Quill call it? Milano? That's right, after that actress, because Quill is, was, a huge dork – and Tony adjusts his course so he's heading right for it.

"Fair enough," Nebula says after a moment, overtaking Tony now that she can see where they're headed.

She gets to the ship first, and does something to make the hatch open and walks up it.

"You are aware this is a suicide mission," Nebula says, as Tony walks up the ramp behind her and then she closes the hatch behind them.

"I've gone on several suicide missions over the last few years," Tony says, making his way to the cockpit. How different can a spaceship be, really, to the quinjet? Shouldn't take him long to figure this out. "And yet – here I am."

Nebula twitches her head in acknowledgement, and slides into the pilot's seat, buckling herself in and reaching out to flip a series of switches and twist a series of dials. Tony watches, committing the process to memory. If they're going to get back to Earth any time soon, they're gonna need to take shifts driving this thing.

"What did you promise?" Nebula asks as the engines fire up, her tone cold and detached, but Tony's already learning to read past that. She seems utterly robotic and unfeeling at first glance, but she wouldn't have been fighting Thanos if she was unfeeling. She wouldn't have demanded to know where her sister was if she was unfeeling. She wouldn't now be launching a revenge mission against her father to avenge her sister if she was unfeeling.

"Years ago, there was this whole thing," Tony explains, sliding into the co-pilot seat and strapping in. "Big invasion of earth – turns out it was at the whim of old sour grapes himself, because of course it was – but the guy who was on the ground, leading the invasion; I spoke to him. Told him that humanity wouldn't just bow down and let these aliens take over. He told me there was no use, they'd win, blah, blah, blah – dude was a cocky little shit. And I told him it didn't matter if we lost. I told him, If we can't save the earth, you can be damn sure we'll avenge it."

Nebula is silent for a moment as she guns the engines and lifts the ship into the air, her hands deft and confident on the controls.

"You did not save the earth," she says, and Tony nods grimly.

"Yeah, no, dropped the ball on that front, apparently," he says, faux-lightly.

"You promised the boy that you would avenge him," Nebula concludes. "That you would avenge your planet."

"Sure did," Tony says, and his voice is iron.

Nebula slants a glance across at him, and there's nothing ahead of them but orange-tinged sky and an entire galaxy, and nothing behind them but dust and grief.

"Then," she says, and there's steel in her voice that matches the iron in Tony's, "we avenge it."

...

AN: I am sleep deprived and can barely keep my eyes open right now, but I had to get this out. Because fuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuck. Fuck. Fuuuuuuuuuuuuuck. I don't even know if this is any good; I just had FEELINGS and I needed to. Express them. Fuuuuuuuuuuuuuuuuuuck.