A/N: Please don't worry, there are no Endgame spoilers or references in this or any chapter until I warn in a precursory note. So you're safe!
CHAPTER FOURTEEN- August 2038
"I don't think I should leave if something is wrong," Bucky said, staring in at Sam Wilson reading a book while getting blood drawn in the lab.
"It's not really…wrong. He just…" Bruce replied. He couldn't explain it. Wilson adjusted holding his book with the hand not being stuck, showing the title Total Applications of Quantum Field Theory.
Bucky pressed a finger against the two-way glass. "You don't see anything wrong with that?" He scoffed, partly concerned for his friend, partly annoyed to be the chauffeur to a teen on a trip across the world. "Seriously?"
"Am I supposed to be panicked he's got different interests since waking up? That's not uncommon with head injury—"
Bucky fumed. "Everything weird is common with head injuries, apparently, because you people don't know anything about them. It's 2038!"
"You people? I think…I should be offended." Bruce may have been completely jaded to 'smartist' mockery, but he also loved the chance to study such an extensive turnaround of Sam Wilson's recovery. The patient remained irritable, sarcastic, and alert with full motor-function. He had occasional headaches but, most bizarrely, had developed not only an interest in but the ability to understand all sorts of scientific studies quickly. "Look, Bucky, you won't be able to do anything if it is wrong anyway. No offense. It's not something you can just—" Bruce slowly swung his fist through the air, making a small 'pow' noise.
"Don't do that." Bucky said flatly.
Bruce pursed his mouth. He was definitely not the funniest Avenger, but he did try ever so often, usually failing and immediately retreating to a cave of algorithms to plot his next joke. The team repeatedly called it 'cute;' Hulk didn't like that distinction either. Hulk had toppled cities for less.
"I've got a couple data sets and stuff for Shuri, too. Let's load up the quinjet and get you on the way. Looks like Little Sam is coming up the drive now," Bruce continued, pointing out the far window.
Bucky groaned. The ball-capped girl trudged down the lane with two massive hard suitcases. She was barely big or strong enough to maneuver them, yet he watched as she waved off one of the security members who came over to help her. The guard pointed her in the direction of the landing pad. Stubborn, Bucky internally groaned, just like good ol' Pa. Bruce returned to shove a box of odds and ends against Bucky's chest. The doctor looked at him seriously for a moment.
"I'm glad it's you taking her. Also, don't mention the," and he waved a hand over his head. "Fair warning."
####
Even though it was not necessary, Bucky made Sam strap herself into the chair up front, damned if he would be responsible for any other injury on Stark's daughter. The two were quiet for all of takeoff, and they'd flown over nothing but water for a while before Bucky glanced over.
Samantha sat tucked up like a rolly-polly, craning her neck to look out the window curiously.
"You look like you've never flown before. Natasha's taken you in one of these before, hasn't she?"
"I've never crossed an ocean," the girl replied in a voice so small he could hardly hear it.
That was a quaint notion. The Avengers bounced from continent to continent almost daily, occasionally planet to planet even, and Sam was afraid of a body of water. She rubbed her hands over her arms, stopping only to rub her legs. However, she still looked on, fascinated.
"Alright," Bucky finally broke in after another half hour, "I'm gonna ask what I'm not supposed to."
Sam looked up at him, shocked but quiet. Her brow furrowed in confusion.
"Are you harming yourself?" He regretted asking the second the words came out, but then he felt the impulse to double down. "I'm asking because the hair, and the scars on your arm, and the limp."
"Those weren't from—" Sam cut herself off. "No, Captain Barnes, I do not harm myself on purpose."
His eyes flickered back over to her at the distinctive choice of words.
Sam looked at her feet. "There was an accident. The Bartons like to bike, motorcycles and dirt bikes specifically. I am…terrible at it, so the last time we did, I was behind Nate on his Ducati, and we crashed."
"Why does Tony not know about this?"
"I was 14, and that was the day Clint told me Tony was sending me to boarding school. I…said some—I screamed several choice things and ran off. Nate came to find me, even though he was a jerk about it, and I got on his bike to go home."
She stretched out her legs into a seated position. "When we were close enough to see Clint waving us back over, Nate raised his hand to waived and hit a ditch, but see, we were right by a bit of a hill. I went flying when Nate skid trying to correct us. They said I smacked a tree—" Sam grabbed her left arm, "—and then my momentum and weight snapped my leg."
Bucky tried to imagine the absolute horror for the Bartons. If Bucky was so worried about strapping her in for one flight, how anxious must Clint have been… He knew immediately why someone wouldn't tell Tony, if it was at all possible to hide it.
"Compound fracture of the left humerus. Compound fracture of the left femur. Damage to the growth plate, so my left leg stopped growing at age 14, resulting in a now one inch difference in length. I tried not to listen when they said how many pins were in there. I stared at the ceiling. They made Nat," Sam swallowed, "explain why we couldn't tell him. So I didn't go to boarding school, and after fourth months I went to Harvard with Cooper. Well, I lived there."
Bucky knew that stare, the one where you know the past can't change so you stopped reliving it, the one where you try over and over to accept the hand you're dealt, the one where you remember everything and feel nothing. Steve used to pull him out by recalling baseball stats incorrectly. Bucky would always snap out to rub his knowledge in that punk's face. He could try a version of that on Sam Stark, something else for them to talk about.
"Sam, what's quantum field theory?"
She didn't change her gaze but scrunched her nose in thought. "Um, like which version do you want? Electromagnetic? Chromodynamic?"
Well, that was nice while it lasted, Bucky thought.
"Do you know what normalization is?" she continued.
So she couldn't pick up on hints. "How about like I'm from the 1940s," Bucky requested.
"Well, they knew some bits in the 20s—"
Bucky frowned on purpose, deeply, comically.
"Right. Basically," Sam thought out loud, making a roundabout motion with her hands, "how… stuff interacts within a—where it is."
"What stuff?"
"Subatomic particles."
"Ok, we're done with that." Bucky had zero intention of going back to the tiny feeling of not following the teacher in school, but he could still gain some context for Falcon. "How smart do you need to be to understand that stuff?"
Sam sat, confused. "That's not a quantifiable question. It's not a specific neural requirement."
"Nineteen-forties—"he reminded through gritting teeth.
"It's my personal belief that you can learn anything if you have the right teacher. If you make the subject relatable and applicable to something in your life, you remember it. So instead of starting with quantum field theory, you could begin with the psychological field theory or how people interact with where they are."
Although a perfectly reasonable association, Bucky snorted. "You don't get out much, do you?"
"You know that I don't. Why else would I be so excited to leave the country I've been in my whole life?"
"Is that why you're so…fidgety?"
"No." She continued to scratch and shift in her seat.
"Do you have a rash?"
"Why did you ask about field theory? Uncle Bruce need a book club buddy or something?"
"Sam, I mean, Big Sam was reading a book."
Samantha's eyes grew wide, and her head snapped over to look at him. To his surprise, she seemed just as concerned as he was.
"Thank you! That's weird, right?"
"He…" She tried to get a spot behind her right shoulder blade. "You mean, he can follow—he is learning very quickly?"
"Essentially. It's like he woke up and was smarter."
"I feel like Big Sam would be a little offended—"
"That's not what I mean," Bucky sighed, but Sam had already quieted.
"So," she began after a long pause, "how worried are you?"
"It's not exactly a health risk, to be smarter, but I just—what else could change?"
Little Sam remained silent this time, holding one arm against her chest, seemingly lost in thought. When Bucky's eyes flicked over to see if she was even still sitting there, he saw her staring at him. He looked again. She wasn't staring at him per say, but her eyes were fixed on his metal arm. Loads of people still stared at the arm, so in public he covered it with clothes and a glove. He thought back to the wedding. He'd been covered; she couldn't have seen it then. Didn't she already know about it? Suddenly, he wished he'd worn more cover than tank top even if it was summer and they were flying to an African nation close to the equator. Why would Sam still be wearing sweats? He glanced again. She was still clutching her left arm against her.
"Are you in pain?" Bucky asked.
Sam snapped back to reality, suddenly guilty and ashamed at her rudeness. She didn't convey the same in her response, abruptly announcing, "I'm tired. Can I go lie down?" She didn't wait for a response, either, and unbuckled to rush back into the jet's cargo area.
Teenagers, Bucky thought.