Chapter 1: Torque
The arm arrives before the man does.
It comes in a matte black case with Wakandan script stenciled on the lid and a courier who won't make eye contact, and when you crack the seals in the back of your lab in Red Hook, you have to sit down on the stool for a second.
You've built prosthetics for eight years. Myoelectric hands for veterans, a carbon-fiber leg for a dancer who went back to the stage, a whole run of cheap printed arms for a clinic in Queens that couldn't afford anything else. You thought you knew what good work looked like.
This is something else. This is vibranium, black and gold, plated like a beetle's shell, each segment fitted so cleanly you can't find the seams without a loupe. And somebody has tried very hard to destroy it. The forearm is crushed inward like a stepped-on can. Three fingers are fused. The wrist servo has been sheared through, and from the shoulder cap a fringe of severed interface filaments hangs loose like the roots of a pulled tooth.
There's a handwritten note tucked under the foam, in a looping, impatient script.
Don't let him tell you it doesn't hurt. It does. The haptic lattice is fully live, he just turned it down. Ask him why. Good luck. Shuri.
Under that, in a different hand, squarer and smudged: She's a genius, you're a genius, he's a pain in the ass. Be nice to him. S.W.
You read it twice. Then you put on your gloves and get to work.
Bucky Barnes shows up at nine the next morning, four minutes early, and stands outside your door for all four of them.
You can see him through the frosted glass. A broad dark shape in a leather jacket, empty left sleeve pinned up. He doesn't knock. He doesn't pace either. He just waits, very still, the way you imagine a man waits outside an interrogation room, and at exactly nine o'clock he raps twice on the glass with his knuckles.
"It's open," you call.
He comes in sideways, scanning. Window, back door, fire exit, the workbench, the tool wall, you. His eyes are paler than they look in photographs, a winter blue, and they stop on you for one beat longer than they stop on the fire exit.
"You the engineer?"
"I'm the engineer." You wipe your hands on a rag. "You're the pain in the ass."
His eyebrows go up. Then, very slightly, the corner of his mouth does too. "Sam."
"Sam."
"He tell you anything else?"
"He told me you'd be early, you wouldn't want coffee, and you'd say the arm doesn't hurt." You nod toward the stool beside the bench. "Sit down, Sergeant. I need to look at the shoulder."
He doesn't sit. "It's James. Or Bucky. Nobody's called me Sergeant since..." He stops. Something flickers behind the blue. "It's Bucky."
"Okay, Bucky. Sit down."
He sits. He takes off the jacket like it costs him something and folds it over his knee, then pulls the henley over his head with one hand, which he clearly has a lot of practice at. And you, a professional, a woman with two degrees and a Stark Industries pension, remind yourself firmly that you have seen a great many shoulders.
You have not seen a great many shoulders like this.
The scar tissue starts at the collarbone. It spreads out over his chest and back in pale ridges where flesh meets the metal socket of the shoulder mount. It looks old. It looks like it was done by people who didn't care whether it healed. Around the edges, newer and neater, you can see where Shuri's surgeons went in and made it right. The rest of him is broad and solid and very warm, and he is breathing slowly through his nose in the deliberate way people breathe when someone taught them to count.
"I'm going to touch the mount," you say. "You'll feel pressure on the interface plate. Tell me if it's too much."
"It won't be."
"Tell me anyway."
You put two gloved fingers on the edge of the socket where the metal meets skin. His whole body goes rigid. Not a flinch. Worse than a flinch. A total, absolute stillness, like an animal going flat in tall grass.
You take your hand away.
"Hey," you say quietly. "Where are you?"
He blinks. His jaw works. "Brooklyn."
"Good. What's it smell like in here?"
"Solder." A pause. "Coffee. Something burnt."
"That's my toast. I burned it at seven." You wait until his shoulders come down a quarter inch. "I'm going to try again. Same spot. You can tell me to stop."
"I won't."
"Then you can tell me to stop and I'll be very surprised."
That gets something. A huff of air through his nose, almost a laugh. When you touch the mount the second time, he stays with you. His eyes are on the brick wall across the lab, his hand flat on his thigh, but he's here.
The work is slow. That's the thing about vibranium. It doesn't bend and it doesn't break, so when it does, every repair has to be built from scratch around the damage, and every new part has to talk to the old ones. Shuri's design runs on a neural bridge, thousands of filaments threaded into the nerve bundles of his shoulder, carrying signals from his brain to the hand and back again. You can rebuild the forearm in a week. The bridge takes longer. The bridge has to be calibrated by hand, one channel at a time, from fingertips to shoulder.
Which means touching him. A lot.
By day three, you've worked out the rules. He doesn't like anyone at his back. He'll tell you about the Dodgers, or the price of a subway ride in 1941, or the three-hundred-page novel his therapist made him read about grief that he hated and finished anyway, but he won't talk about the arm. He has old manners that surface at odd moments; he stands when you stand, he holds doors, he calls the woman at the coffee cart ma'am and makes her blush. He brings you plums on day two. Wakandan ones, dark purple, in a paper bag.
"Got a guy," he says, when you raise an eyebrow.
"You have a plum guy."
"I have a plum guy." He sets the bag on your bench very carefully, like it might go off. "It's a long story."
"I've got all day. I'm rebuilding your wrist."
He looks at you for a moment, the way he looked at the fire exit the first morning. Then he tells you about a goat farm in Wakanda and the neighbors who used to leave fruit on his step and the first time he slept through the night in seventy years. You don't say anything. You just keep working, and he keeps talking, quieter and quieter, until he stops in the middle of a sentence and you look up to find him watching your hands on the forearm plates.
"You're gentle with it," he says.
"It's a beautiful piece of engineering."
"It's a weapon."
"It's an arm." You turn a micro-driver a quarter turn. "Somebody built it to hurt people once. That was the old one. This one, somebody built so you could hold a cup of coffee without crushing it. I'd like it to stay that way."
He doesn't answer. But on day four, he walks in, sits on the stool, and takes his shirt off without being asked.
It's day six when you finally find what Shuri meant.
The forearm is reattached. The wrist moves. The fingers curl and uncurl at his command with that soft, satisfying mechanical whisper. You run the motor diagnostics three times and they come back perfect. Then you run the sensory diagnostics, and you sit back on your stool and stare at the screen.
"Bucky."
"Mm." He's flexing the hand, watching it. There's something careful in his face, almost wonder.
"What's your haptic sensitivity set to?"
The fingers stop moving.
"Shuri built a full sensory lattice into this hand," you say slowly. "Pressure, temperature, texture, every bit of it routed back up the bridge. It's better than what most people have in their real hands. And somebody went into the firmware and dialed it down to four percent." You look at him. "Four percent. You can barely tell if you're holding something. You'd feel it if you put your hand in a fire, but you wouldn't feel me."
He's looking at the brick wall again.
"Was it you?"
A long silence. Outside, a truck rattles past on Van Brunt Street, and somewhere upstairs a pipe knocks.
"For a long time," he says finally, very low, "anything I touched with that hand, I was hurting. I didn't want to know what it felt like. I didn't want to know what they felt like. It was easier to just..." He opens and closes the metal fingers. "Not."
You don't say anything for a minute. Then you pull off your right glove.
"Can I try something?"
He watches you. His throat moves. "Like what?"
"I want to turn it up. Not all the way. Fifty percent. And then I want you to tell me what you feel." You hold up your bare hand. "You can tell me to stop."
"I know." His voice comes out rough. "You keep saying."
"Because I keep meaning it."
He looks at your hand for a long time. At your face. Then he nods once, short and sharp, like a man agreeing to something on a battlefield.
You type in the command. On the screen, the bar slides from four to fifty. Somewhere in the shoulder mount, a filament array hums awake.
Then you reach out and lay your bare palm flat against the palm of his metal hand.
He makes a sound you'll be hearing for weeks. A ragged, startled intake of breath, like a man surfacing from deep water. His whole arm locks. His eyes go wide and dark and fixed on the place where your skin meets the vibranium, and you feel the fingers tremble, very faintly, against yours.
"Bucky?"
"Warm," he says hoarsely. "You're warm. I can feel your..." He swallows. "There's a callus. Base of your thumb."
"From the micro-driver."
"I can feel it."
You don't move. You let him feel it. Slowly, so slowly it's barely a movement at all, his fingers fold down until they're laced between yours, black and gold against your skin, and he holds your hand like it's the first thing he's held in eighty years.
Then his eyes come up and meet yours, and they aren't careful anymore. They're hungry.
"Turn it up," he says.
Your heart is slamming. "That's not a good idea. You need time to adjust to fifty before we go to..."
His grip tightens. Not hard. Just enough that you feel how carefully he's holding back.
"Doll," says Bucky Barnes, very quietly, "turn it all the way up."