So after I read Avengers One-Shot fanfic "Retribution" in Fanfiction.net as well as some SPOILERS from Episode 4 of The Falcon & The Winter Soldier, this pops-out my idea regarding toward that moment.

DISCLAIMER: I do NOT own anything. The Avengers are belongs to Marvel & Disney. I own OC only. Thank you.
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The world is watching. Something snaps towards the new Captain America, John Walker against Sam Wilson & Bucky Barnes. But before it goes from bad & worse, an unexpected happen.

???: Hey, jackass.

Walker turns around, only to get punch in the face and got kick the body to the ground. Sam & Bucky look at the newcomer. It was a young man in early 20s with a red hair and wears a black & red denim leather jacket, red gloves & boots and a wrist gauntlet strap on the left wrist. His blue eyes was covered by a black domino mask to conceal his identity. However, the most shocking part was underneath the jacket is the exact copy of Captain America suit back in WW2. This is Nomad.

Walker: Who in the heck are you huh?!
Nomad: That Shield is NOT belongs to you. It belongs to someone worthy to carry his legacy. You are not Captain America but a show-off nobody who disrespects the man who is a legend in both WW2 and today!
Walker: I don't care what you're saying, kid but go home! You're just a stupid Captain America fan.

Walker's words piss-off the man as he gives him a Death Look which Bucky recognize that look before.

Nomad: Who are you calling me stupid Captain America fan?! Your skills are sloppy and unrefined while Cap despite only a year in military experience, he did save more soldiers & people in the war than you.
Walker: You dare to mock me!?
Nomad: And how dare you mock Captain America! The real Captain America! You're NOT worthy of that Shield!

Walker had enough and throws the Shield but to him, Sam, Bucky & everyone(even Zemo & Sharon) surprise, the man caught the Shield...with one arm!

Bucky: *remembers the time he caught the Shield when he was brainwashed by Hydra back in Washington with one(metal) arm* Holy Crap!
Sam: Damn!
Walker: *shock* What the f#©€?
Nomad: Language! There's only one person that can stop you and that's ME!

He throw the Shield to Walker and hit him before he charges. Walker also charge and the two had a fight. While the two fighting, both Sam & Bucky were left standing but analyzing the movements of that young man. They recognized his fighting skills were both Steve and Natasha...? Walker found out he was exhausted because his opponent was so fast & agile so he headbutts him that he got back away and touch the forehead in pain.

Nomad: You hit me! Captain America never does a dirty trick like that!
Walker: I'm gonna beat you and end this fight!

Walker roar and uses the Shield to press the attack but Nomad defends himself when he activated the wrist gauntlet...revealing a Holographic version of Captain America's Shield. Sam & Bucky's eyes were widened & jaws drop while everyone were also did the same.

Zemo: Is it me or that kid(Nomad) had future version of Captain America's Shield? Am I hallucinating?
Sharon: *shock tone* No. You're not.
Walker: *saw this & shock* How?

Nomad smirks before he sneak attack him with a kick and throw the Holographic Shield as it bounces back to hit him again before it returns back to Nomad. Walker grunts in pain and look at him.

Walker: You! How the heck you fight so fast?
Nomad: I learned that by my parents and myself. You know why I am so fast?

He takes off the domino mask, revealing a quite resemblance of Steve Rogers but younger as he smirks that similar of Black Widow.

Nomad: Because I can do this all day.

And that moment Sam & Bucky saw the face of the man, they found out that he is the son of Steve Rogers...and Natasha Romanoff. No wonder he got their skills & abilities. He had both of his father's Super Soldier serum and his mother's in his blood. Not to mention, his red hair looks recognizable. The question is...where did he come from or is he just time travel?

Walker: Why you...! *Stands up and roaring charge*

Nomad fires a Widow Bite from his Wrist Gauntlet and shocks Walker unconscious, ending the fight. Everybody around the scene left in shock & speechless. Nomad ignore everyone as he picks up the Shield and went to the duo.

Nomad: You should kept what Steve Rogers promise, Sam Wilson. *Gives the Shield to Sam*
Sam: Yeah. *Received it* I should have listen to him right now.
Bucky: Then what about him? *points to unconscious Walker*
Nomad: Don't worry. The government will take care of it.

Secretly, Nomad has an AI companion called "J.O.C.A.S.T.A" to hack the files about Walker and when they found out for background check, they were disgusting. So he order the AI to release on every media & network right after the fight. Nomad felt someone gonna interview him and decide to leave.

Nomad: I'm gonna go now.
Bucky: Where are you going?
Nomad: *smiles* Whenever something happens, I'll be with you until the end of the line.

And with that, Nomad runs so fast and vanishes.

After the incident, Walker got kicked out by the government and was shunned by everyone after a leaked information about his disgusting behavior against not only Cap but to late Tony Stark and the Avengers exposed the social media. Heck, it also expose the Sokovia Accords, the Raft and the S.W.O.R.D. involvement in Westview that try to frame Wanda Maximoff. Thankfully after the fight against Agatha Harkness, Wanda decide to penance herself to redeem her sins and vanishes before Monica talks to her.

The rest such as Thaddeus & Everett Ross and the others who created & supported the Accords were arrested for violation against the 2nd Amendment while Monica and other S.W.O.R.D. agents were also arrested as well. The video about Spider-Man is Peter Parker by Mysterio was revealed to be a HOAX which damages J Jonah Jameson's reputation of being an anti Spider-Man. It happened several weeks after the Blip event.

Speaking of Spider-Man, Peter Parker decide to end his relationship with Michelle Jones due of his pressure of both a normal life and his vigilante duty. MJ tried to reassure him but Peter snaps and told her to leave him alone. So that's the end of him & MJ's love story. But there's a second chance of love for Peter as he meets Felicia Hardy aka Black Cat and the two became more than just a friends.

Several days later, Sam Wilson became the new Captain America and people got what they deserve him as the next Cap while Bucky train the New Avengers: Peter Parker/Spider-Man, Felicia Hardy/Black Cat, Kate Bishop(who is Clint's apprentice), Rhodey/War Machine, Scott Lang/Ant-Man, Hope Van Dyne/The Wasp and Kamala Khan/Ms. Marvel.

~Elsewhere~
Nomad aka James Rogers was in Los Angeles, disguise the same clothes that his father used when he & Natasha were on the run from SHIELD/Hydra agents with a LA Dodgers cap as he witnessing his uncle Sam inaugurated as the new Captain America that he smiles. He also received from J.O.C.A.S.T.A that Bucky train the New Avengers and an ongoing trial against Ross and other cohorts of the Accords as well as the S.W.O.R.D. agents involvement about Westview incident.

JOCASTA: Looks like our mission is done, Cap.
James: Eyup, JOCASTA. Mission Complete.

James walks away and heads towards an unknown location where he saw two figures, also in disguise unnoticed by everyone were standing towards the screen where Sam inaugurated as new Cap.

James: My work is done. Is anything I can do more?

The two figures turn around, revealing.......Steve Rogers & Natasha Romanoff!

MCU Fans:

https://www.youtube.com/watch?v=3WMBFghFCIg

Steve: No, son. I think you're done.
James: Wooh. Thanks, Dad.
Natasha: I'm still can't believe why those fools try to kidnap us in the first place to fooled our friends that we are not together.
Steve: I don't know but at least, James and the AI did rescue us.

In reality while Tony Stark did sacrifice and died a hero after the final fight against Thanos, the death of Natasha in Vormir and Steve stays in the Past to be with Peggy Carter in the end was a FAKE! It is reveal that the shape shifting aliens known as the "Skrulls" kidnapped them just before Ultron introduction & before the Civil War fiasco that split the Avengers apart and was replaced 2 Skrulls disguise as them to fooled the Avengers that led Thanos succeeding to snap half of the universe. They try to ruined the Avengers legacy and even they send several of them to disguise as politicians that will led to create the Sokovia Accords.[1]

The two were imprisoned in a Skrulls facility to be experiment and torture both physically & mentally by Skrull scientists but they did NOT submit their will no matter how many they got hurt or hit them. During their imprisonment, they found some people from other planets, few of them were humans also imprison as well. However, they also found the real Carol Danvers aka Captain Marvel. It means that Carol who appeared to Nick Fury several years ago and in the aftermath of the Snap was a Skrull spy in disguise. No wonder that one is self-righteous and arrogant person while the real one was dependent but wise person.[2]

Then James Rogers, their future son and the future Captain America shows up and rescue them and the others. They led a prison break out before they escape to a Skrull jet for a rendezvous point. James explained that his future was altered due of Steve stays in the Past and be with Peggy that led Kang the Conqueror, a time traveling alien warlord invaded the future and killed the Avengers while James managed to time travel back to the Past via Quantum Time Machine that Hank Pym left and discover the horrible truth behind the Civil War fiasco. He ends the explanation that he can't return back to the Future. After returning some of the prisoners back to their home planets, the trio and Carol return to Earth where the trio & Carol split up for some reasons.

While Steve and James were checking about the Accords, Natasha went to Europe and found Yelena Belova. With them are her old associates from her past and the two fought Taskmaster. After this, the two spies return to Steve & James who found some information about the Accords.

They survive the Snap and they decide to hide themselves in shadows before they strikes the disguised Skrulls. After the final fight and the Blip, both Steve & Natasha were secretly pay their respects to Tony before taking down some Skrulls who created & supported the Accords in shadows while James knocks out the Skrull Cap in Vormir and returning the Soul Stone in the process. Steve uses a camouflage device that he borrowed from James to disguise as an Old Man Steve and gives him the Shield to Sam before leaving.

After this, Steve & Natasha were married in a small church with their different alias as "Steven Grant" and "Natalie Jones" with James as the Best Man and Yelena as the Maid in Honor. Plus, they adopt Yelena as their adoptive daughter and they live a normal, simple house in Brooklyn while James decide to check what events after the Blip.

It wasn't long when the Elementals attack occurs in London as Peter/ Spider-Man was there due of the school field trip. JOCASTA show a video of Quentin Beck/Mysterio exposing Peter Parker is Spider-Man to made him a menace while himself being a 'hero'. Upset towards that kid will be chase by the authorities because of the damn Accords, Steve ordered his future son to expose the video as a "Hoax" to save Peter's reputation.

The family were having a good time watching a TV until they notice a new show that reveals Westview as Wanda in 50s and an alive Vision in a business suit appears in some kind of sitcom show. Horrified to see her inside, the Rogers family went to Dr. Strange(who also were surprise to see Cap & Widow alive) about this. They found out from Dr. Strange that Wanda mix her Hex and a Chaos magic to create a reality that turns the town into her fantasy show, not knowing that it bring a consequences.

Hoping to bring Wanda out, Steve, Natasha, James & Yelena sent out a rescue mission by themselves to save her. They found out the S.W.O.R.D. organization was also involve the Westview as well. Feeling that the organization is also another Hydra, they secretly check the background before taking them out inside just as Wanda fight against Agatha Harkness.

After leaving Westview by flying before Monica try to talk with her, Wanda was found by the Rogers family and ask her why. They felt sympathy that Wanda was lose everything she cares: her brother, Vision and herself.[3]
(Note: I personally don't like Monica after she said that line that made me saying: 'WTF?'. Did you know her mother were best friends with Captain Marvel? That's the reason why she said that stupid line that made Wanda into villain.)

She was angry to Steve & Natasha that they abandoned her but the two told her that it was Skrulls kidnapped them and replaced by them. Reading their minds that the two were telling truth, Wanda was shock and cried as the two hugged her to comfort. Wanda was stayed in Sanctum Sanctuary to redeem her sins as Dr. Strange helps her to control her chaotic powers.

As the Rogers family were gonna rest for good, a new Captain America was introduced but it was John Walker who was nothing but a jackass nobody carrying the Shield who disrespects not only Steve but also the late Tony Stark. Yet again, they went to another mission where they check and found Walker's background and that's where James appears and strikes the fake Cap happened.

James: Yeah. I guess we gonna rest for now. I got a call from Carol earlier that she confronts Monica before the trial and told the horrible truth that made Monica shock in disbelief before Carol went to space.
Natasha: Oh. I heard that she finally take care of that Skrull who disguise as herself while the Guardians especially Thor were shock as well.
Steve: So where is she?
Natasha: I think she joins with them.
James: Good for her.

Yelena & Wanda came, wearing a LA Dodgers shirt & a cap with ripped jeans while Wanda still wearing Nat's red jacket with a blue Avengers T-Shirt underneath, black jogging pants and has glasses to conceal her face. They were holding some hotdogs & drinks.

Yelena: Hey, Mom, Dad and James. The baseball game is starting. Come on.
Wanda: We're gonna lost our seats by them.
Steve: Right. Let's go. We don't want to stay standing in the game.

They laugh as they went to a LA Dodgers baseball game. Life is good for them.

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AND DONE! After reading that One-Shot fic in Fanfiction and Episode 4 of The Falcon & The Winter Solider show, I kinda bring the Romanogers couple and their golden child(Pun Intended!), James Rogers to fix the messes of what MCU writers did. Adding Yelena Belova before Black Widow movie was release yet, this does put a smile on my face.

1 - The Skrulls are already infiltrating Earth and disguise anyone. Inspired on the Invasion arc of "Avengers: Earth's Mightiest Heroes" animated series as well as Rhodey was a Skrull theory, Steve was kidnapped along with Natasha by the Skrulls before Ultron incident and Civil War. That's the reason why the two ignore each other after SHIELD/Hydra fiasco. Ultron want to destroy the Avengers because the Skrulls are already here and disguise one of them and the Sokovia Accords was created by them. That's my theory right there.

2 - Watching a video about a deleted scenes of Age of Ultron where one shows a stand-in actress played Carol Danvers/Captain Marvel did cameo in an alternate deleted ending. I don't know what's the name of the actress but she is way better than the self-righteous & arrogant that is Brie Larson. Her disguise as a Skrull spy appeared 2019 trash movie with the same name as well as Endgame made more sense she is just annoyed 'Mary Sue' type character.

3 - Speaking of Captain Marvel movie, some of writers of that trash movie may have working with the show runners created WandaVision show that they added Monica, whose her mother was Best friend with Captain Marvel and her line was plain, stupid 'WTF' line I've ever heard since Arrowverse Iris West's infamous line: "We're the Flash!"(🙄). They were same guys that turn Wanda into villain in the upcoming Dr. Strange 2 movie. I feel bad for Wanda. I give her a happy ending instead of that crap.

Anyways, I hope you like my new One-Shot story. Thank you.