Disclaimer: never did and never will own it. Marvel does.
Spoilers: canon until Captain America: Civil War (and the post-credit scenes of Black Panther).
Timeline: supposedly happens between Avengers Infinity War and Avengers 4.
Steve was quite easy to find, in the control room. What was strange was that neither Tony nor Natasha were here.
"I called Shuri about your memory lapses. She told me it was normal, a defence mechanism of the brain. Since you don't want to forget what you did as the Winter Soldier, it tries to shun everything that could make you remember."
Tony entered the room, but Bucky ignored him. His eyes were on Steve, who looked relieved by Shuri's reassurance.
"I owe it to those I killed. I didn't have the choice but I did it. The least I can do is to remember each and every one of them."
"That's because you say things like this that I forgave you," said Tony, sitting down next to them. "It doesn't mean I like you, but still."
"I know you think that you didn't revenge your parents since you didn't kill me, but remember that death ends quickly. Guilt tortures you till the end of time. You are avenged every minute I live."
Steve peered at Tony.
"You know there had been alterations to make his room soundproof, don't you?"
"So he can kill without alerting everybody?"
"So he doesn't wake everyone sleeping on the same floor every night with his nightmares."
"That loud, huh?"
"I don't know," replied Bucky, annoyed. "Maybe I screamed louder when they wiped out my mind, but they put a teeth shield in my mouth and it muffled the sounds, so it probably doesn't count."
"I'm not pitying you," Tony stated.
"Good. Neither am I. Pitying you, I mean."
Steve laughed. Then Natasha came in and sat next to them.
"We may have a problem. The one Barnes calls Summer is not the Summer Flower, but I doubt her choice of name is that innocent; she doesn't even sound sure of her name. Maybe she was just instructed to give this answer to Barnes if he actually asked for her name. It looks like a plan similar to those of the KGB, even though it's probably HYDRA behind it. So I think the real Summer Flower is here, maybe using the girl as bait with her open admiration for Barnes. See if he relents and lowers his guard."
She looked at him, in almost full Winter Soldier garb. She had seen him only moment ago and she knew he still had the knives in his pockets. Somehow she doubted he would lower his guard. Even in Romania, with no weapon, he had not been taken off guard.
-o-o-
Tony snickered, having had the very same thoughts.
"Good luck to her. So, you're telling me we have another assassin in the compound? Infiltrated for a long time?"
She shook her head. "I don't think so. Probably counted on you saving the girl before making a move. Would insure a perfect cover. HYDRA's brainwashed victims are notoriously unreliable."
"A new one since we have the girl? Nobody comes to mind."
"The doctor you recruited to help her get better, since we can't send them all to Shuri," Steve said suddenly.
"Good point, Capsicle. At least, your brain was not entirely frozen."
"I'm not dead yet, Tony."
"The girl is innocent, then? Maybe was not even brainwashed?"
"Oh, she was brainwashed, all right. She's confused about many things and the more you interrogate her, the less sure she is of her answers. Though I'm pretty sure she was not indoctrinated with the program you found. Or maybe she was brainwashed to the contrary of what we believe. Not to kill the Winter Soldier, but to love Bucky Barnes."
Bucky tipped an imaginary hat to her. "And here I thought someone could love me as I am. Nope, would require brainwashing," he said sarcastically.
"Not everybody can be me," Tony said.
"She can't be that innocent. She killed several HYDRA people and it didn't seem to bother her. It doesn't fit with the fact she stated she had only been trained here. Besides, there's that thing about the 'With the compliments of Tony Stark' comment."
"Yes, it surprises me a little, to be honest, because I indeed asked that from some people. But she wasn't one of them."
"Something else bothered me, but probably I just don't know her enough... Miss Potts doesn't strike me like the person to give information about her possible target to a brainwashed killer, no matter how sweet she may look. I mean, remind me how many times we have actually seen Pepper Potts here?"
"She is meddlesome like that," said Tony, "and could have done it. But she has nothing against you, so she wouldn't deliberately send someone after you. Besides, you're right, she doesn't come here often and certainly not where we've been keeping your girlfriend. So what? The Summer Flower made her believe she was Pepper? FRIDAY, analysis of all the times Miss Potts came to the compound in the last four months and where she went."
"Analysis in progress."
The results were edifying, as it appeared that Pepper was at the compound when she was not even in New York, but it was always at the same time Tony was absent.
"So I can't meet her by mistake and nobody else here knows her schedule. The replacement knows hers a little too well, though."
So they set a watch over LeAnn Daniels, who seemed a perfectly harmless psychologist and doctor to heal mental manipulations, while Bucky continued his daily routines. The interrogation of the pilot and the radio operator had given nothing, since they had both bitten their cyanide capsule as soon as they had been caught. Bucky even participated to some missions, though his pilots were closely monitored. Summer didn't manage to escape from the compound a second time. But Pepper made a new appearance and, unbeknownst to her, she was followed closely by several pairs of eyes.
-o-o-
She slipped in Summer's room, having no difficulty whatsoever with the electronic lock.
"Hello, Summer, how are you?"
"Pepper! I'm glad to see you!" Summer replied, embracing the redhead.
"So, how is it going with Sergeant Barnes?" 'Pepper' asked with a mischievous smile.
"Nothing's going on," Summer said, dejected. "I mean, I managed to replace the pilot, like you told me, so I did get to spend some time with Bucky."
"And?" 'Pepper' pressed.
"He's the sweetest guy ever," she said dreamily.
"Don't you dare laugh," Bucky growled at Steve in the watching room.
"I don't know. I remember you laughing at me when I kissed Sharon."
"Punk."
"Jerk."
"And?" the false Pepper asked again.
"And we were attacked! Can you believe my bad luck? Because of that, Mr. Stark is keeping me under closer watch. No way at all to get out; I haven't been able to go watch Bucky ever since. I will never see him again!"
They noticed that no matter what 'Pepper' said, Summer never mentioned the attack by the Winter Soldier, nor her discussion with Natasha. Bucky also noted with relief that she didn't say that she had kissed him. But the conversation didn't tell them much. The fraud was trying to know what Summer did – or eventually what she had seen the others do – but she didn't push her to do something else, like she apparently did before.
The following day, Tony was told of the visit and he was glad that his staged absence had indeed started what they had hoped for.
"FRIDAY? What are the results?"
"Nobody tried to access Miss Potts's planning," she announced.
Steve frowned.
"What?"
"Ever since we said we were going to keep an eye on Pepper's appearances here, I bugged her phone and computer to be sure to know who accessed her schedule and Ant-Man is keeping an eye on her in case she says it to someone. How's that, nobody? Not ever herself?"
"From the analysis, the schedule was updated on its own. No interference from outside."
"We have a hacker better than me!" Then he winked at Bucky. "I'll ask for her help. You'll see, she's really good. Once she's stable, I may even offer her a job."
"The cameras in her room, we can access them twenty four hours a day?"
"Yes, but I'm not turning them on during the night. I'm not a voyeur, Barnes."
"Never wanted to imply that, Stark. Just turn on the mikes during the night."
"Why?"
"Because if she's brainwashed, rather innocent and was forced to do horrible things, she's bound to have nightmares. If she does, then turn on the cameras, and warn me. It will give me an excuse to wake up."
"Okay, let's start it all! Oh, hello, Wanda, Vision!"
"War council?"
"No, just a tiny spy thing or killers after our Manchurian Candidate. Nothing to worry much."
Wanda glanced at Bucky. They had been teammates and she liked him. She sat down. "Explain."
So Tony did and Wanda volunteered to fetch Summer for the hacker thing. Bucky disappeared, but somehow, Tony was sure he was still around.
-o-o-
There were traces of tears on Summer's cheeks and her puffy eyes were also duly noted.
"What happened, kid?" Tony asked.
"No-nothing. I'm a bit lost, that's all."
Tony kept staring at her. She looked down and mumbled, "I miss Bu– Sergeant Barnes."
"You've met him only once. How can you miss him?"
"Twice. The second time, he was conditioned as the Winter Soldier."
"And you still miss him?"
She shrugged. "My doctor didn't say I was sane." She tried to smile. "But I'm not here to whine about my problems. Do you have a new exercise for me?"
"Indeed." He explained the thing to her, careful not to tell her it was about Pepper's planning. She grinned.
"It's easy! Did you forget? You gave me almost the same exercise two months ago, except that I had to hide all accesses. I just have to undo the bit of code here... and there... and here you go!"
"Your memory is getting better and better," he commented briefly before sending the results to FRIDAY.
She shrugged. "You'll have to find more complicated than that to see if I'm really good."
"I'll think about it. Thank you. By the way, do you remember your name by now?"
"Yes!" she exclaimed. "It's..." She faltered. "Summer. I think." Then she looked around, almost as if she expected Bucky to come out of nowhere. The fact that he was really around did not ease Tony's worry. "May I... wander around a bit?"
"Still trying to see him?"
"Well, you don't seem really decided to name me his official pilot, so..."
"You know he is a pilot also, don't you?"
"Yes, but it's better when there's still a pilot in the helicopter after he jumped off from it. No waste of materials and the ride back is assured."
Tony laughed. "True. I'll think about it, if it guarantees that you stop trying to get out of your room."
-o-o-
As soon as she left, Bucky and Steve appeared.
"See how it feels to have your identity usurped?" Bucky asked. "You're fortunate it's not on TV yet and that it wasn't for accusing you of bombing a building."
"So we have a false Pepper and a false me haunting this compound! How is it possible? FRIDAY, analysis of all my interactions with Summer."
"By the way, Tony... Why don't you ask Pepper about the planning and who she shared it with? If you tell her someone is trying to frame Bucky while impersonating her, she will certainly help you," Steve suggested.
"You know what? If you don't find the answer by ourselves, I just might do that."
"Oh, look, you were here yesterday!" commented Natasha, who had just arrived, followed by Sam. "I'm a bit hurt you didn't come see us."
"If I had known I was here, I would have come, believe me." He sighed. "And here we go for loong hours of listening to probably uninteresting conversations with a love-struck brainwashed girl."
"I have an objection," said Bucky. "Why waste such a complicated operation on me? If they have an assassin as skilled as that Summer Flower and people capable of masquerading as Miss Potts and you so well, why use a mostly innocent girl to bait me – if it is supposed to work? They are inside New Avengers Facility with us none the wiser and they're just trying to get back at a renegade? Makes no sense. It's not as if I knew any of their secrets or things like that! They even have someone spying on you, Stark, so shouldn't we plan for a bigger threat?"
"They infiltrated us like they infiltrated S.H.I.E.L.D? But S.H.I.E.L.D dealt with secrets and could unbalance governments if they wanted. Stark Industries and the Avengers don't, do they?" Steve said.
"I have a few technologic secrets," admitted Tony, "and well, the Sokovian Accords tried to make sure that the Avengers couldn't unbalance governments. Except that we don't really follow them. Are you telling me, Barnes, that I should start to suspect everyone?"
"The Avengers are probably clean and also the people who are with us for a long time," Steve supplied.
"Okay, okay. Are we overreacting? If we start a purge of both Stark Industries and New Avengers Facility, it will be a massacre, which could lead to another civil war. We're only getting back together, because there was a threat and we had to regroup. I'm not sure we would survive another scission."
"No need to dramatise yet. Let's analyse what we have, but eliminating the spies on Pepper and you, the people impersonating you and whoever is possibly manipulating Summer will alert the others if there are others. It's only at that moment that we will need to wonder about a purge on a greater scale."
"Can you tell your FRIDAY to give me access to the videos of the false Pepper and you?" Bucky asked. "I'll watch them for you. It will give me something to do during the nights."
"You're my saviour. But will you know what is suspect and not?"
Steve and Bucky looked at each other and, to the surprise of the others, burst out laughing.
"Don't go looking at his room," Steve advised. "He dismantled the air conditioning because it was making a suspect noise."
"Sorry. A bit paranoid."
Sam looked at Natasha. "Something shared by a few of us."
She had a sweet smile for him.
