At the Compound, Goku, Steve, and Tony returned from their trip to 1970 New Jersey. Everyone was relieved that they were back. Goku goes up to Wanda as she quickly hugs him.
Goku: Hey, honey. I'm back as I promised.
Wanda: Please don't make me get worried like that.
Goku: I will. Plus...
They stop hugging as they look at each other.
Goku: I met Peggy by accident.
Wanda: Peggy Carter? Really?
Goku: Yeah. I entered her office without knowing she was in there and she asked me questions.
Wanda: Did you tell her your name?
Goku: Not at first, but when I uses Dad's last name, it made her remember him, especially in how I am when I talked to her.
Wanda: Well, I can understand, since you two are very much alike.
Goku: She pointed that out, too. And then I hugged her to give her some comfort.
Wanda: How did she react?
Goku: I could tell she was surprised but hugged me back. As I was going to leave, I said my real name and left.
Wanda: *smiles* That's sweet of you, Goku.
Goku smiles as they waited for all checks to see if they have all the stones. Soon, Clint arrives with the Soul Stone, but Natasha was not with him. Goku was confused as he tries to sense her energy, but couldn't find it, most likely because of where she went.
Bruce: Clint, where's Nat?
The silence from Clint tells them all they need to know. Goku went pale as went down on his knees, looking lost as tears went down from his eyes.
Wanda goes down and hugs him while tearing up as well. Everyone stood there silently, mourning the loss of Black Widow. It was heartbreaking they lost her, as she sacrificed herself to get the last Infinity Stone for them. Soon, Goku wipes his tears and stood up. He stood there, serious, walking towards the machine. Everyone looks at him.
Steve: What?
Wanda: Goku, what are you-
Goku suits up as he turns on the machine and quickly steps into the platform.
Tony: Goku wait!
Scott: Don't do it!
Bruce: You can't!
They tried to stop him by turning the machine off, but it was too late as Goku disappears into the Quantum Realm.
Wanda/Steve: GOKU!
*Goku's POV*
Goku travels into the Quantum Realm, looking for Vormir before making a quick turn and appearing in the abandoned world. He runs forwards as he nears the edge of a deep ravine. There, he sees, thanks to his advanced Saiyan sight, the body of Natasha laying on the floor of the ravine.
Goku: Mom.
Goku uses Instant Transmission to send him down to where Nat's body is at. He stood there as he looks at Nat, remembering what Vegeta told him about the Soul Stone and how Thanos sacrificed his daughter Gamora to get it. He thinks the moments he had with Natasha, who is caring, funny, supportive, and gentle to him, made her the only mother figure he had, much like Steve. As he thinks about this, he grits his teeth as tears go down.
Soon, visions of him seeing his grandpa's trampled body came into his mind, as he stares at the body of Black Widow.
Goku: No...I won't leave you like this, mom. You have family and friends to come back home to. I won't let you stay here on your own.
He wipes some tears as he gets serious. He then charges up his energy and yells out, with a blue aura covering his body. Soon, it dies down, as he transforms into a Super Saiyan God.
(Yes, this is my custom way to transform into a Super Saiyan, so don't get upset because these are from different movies)
Goku kneels down and places his hand on Nat's stomach. He then lets out his fiery red aura and transfers it to Nat's body. Soon, her body gets engulfed with the aura as Goku prayed this would work.
After a while, he stops as he goes back to base form as the aura fades away.
Goku: Mom?
After a few seconds of silence, Goku lost all hope. Until...he hears a cough as he sees Nat awake, coughing but alive. His face lights up as Nat opens her eyes.
Goku: It worked! You're alive!
Nat: What...happened?
Goku: Oh, mom! *lifts her for a hug*
Goku: Thank goodness it worked!
Nat smiles as she hugs Goku back.
Nat: Can you ease yourself up? You're crushing me.
Goku: Sorry, it's just that...I didn't want you to be here all alone and far away from us. I wouldn't know what me, Bruce, Clint and the rest would do if we were to lose you.
Nat: I know. Sorry for that, honey.
They get up and they stare at each other.
Nat: Thanks for bringing me back, Goku.
Goku: No problem, mom. Now, let's go back home. Though, I'm scared of what Wanda and dad are gonna do to me when we get back.
Nat: You came here in a rash decision, didn't you?
Goku: Ehehehehe...yeah. *sheepishly*
Nat: *shakes her head* You're still the same as always, haven't you?
Goku: Yeah. Anyway, let's go.
Nat: But what about the Pym Particles?
Goku: I got a few extra for both of us. *passes her a tube*
Nat: Alright, then. Let's get back to our family.
Goku nods as they suit up and went through the Quantum Realm, heading back to their time.
*at the Compound*
Everyone was waiting anxiously for Goku to return. Wanda couldn't believe her husband has taken a rash decision like that. She just hopes he hasn't done anything stupid.
Soon, the machine opens, and they turn and see Goku and Natasha there. Everyone was shocked that Nat is alive, mostly Clint as he witness her sacrificing her life for him to get the Stone.
Clint: Nat?
Nat: Hey, Clint.
They stepped off the platform and quickly Clint rushed in and hugs Natasha.
Clint: I thought I lost you! How did you-
Natasha: I thought so too. Until Goku managed to bring me back to life.
Clint: *looks at Goku* Thank you, Goku. For bringing her back.
Goku nods as he winks at him. Bruce joins in and gives them a big hug. He's happy Nat is brought back, alive. Goku turns and was met by a stern look from Steve and an angry one from Wanda.
Steve: Son, I know how you felt, and I'm glad you brought Natasha back, but...
Wanda: Next time, make sure you let us know before making such a decision.
Goku: O...okay, guys. I'm sorry. *chuckles nervously*
Wanda: Next time you do that, I'll stop cooking for you.
This shook Goku to his core.
Steve: Sounds like a good idea, Wanda.
Goku leans down, defeated as everyone was chuckling at the scene.
*later*
After a small chat, Tony, Rocket, and Bruce built a gauntlet that held all the Infinity Stones. The gauntlet is red with golden stripes, akin to Tony's Iron Man suit.
Everyone gathers around as they look at the gauntlet.
Rocket: All right. The glove's ready. Question is, who's gonna snap their freaking fingers?
Before anyone could say anything, Goku spoke.
Goku: I'll do it.
They look at him, as he stares at the gauntlet.
Scott: Excuse me?
Wanda: What are you doing?
Goku: Don't worry. I can withstand it. No problem.
Steve: Wait, Goku, at least let us decide first-
Goku: I'm tired of waiting for this, dad.
Goku looks at him in pure seriousness and sadness. Everyone stood there silent as he continues.
Goku: I'm tired of waiting. Every day when I was training for a year inside the Chamber, I had these nightmares of everyone that were erased by Thanos come up to me, telling me I failed them, I failed everyone in the universe, I failed every single one of you. And one of my more damaging nightmares...was seeing all of you turn to dust right in front of me.
Everyone couldn't say anything as there was nothing to say about what they just heard. They feel bad that Goku felt so blamed for what happened that these nightmares occurred. Wanda stares at him as he wipes a tear from his face.
Goku: So please, dad. Let me do this.
Everyone looks at Steve as he stares into Goku's eyes. He can feel the immense pressure his son is feeling, wanting to correct a wrong he shouldn't blame himself for. After a short while, Steve sighs and nods.
Steve: Okay, son. We'll let you do it.
Goku nods as he looks at the Gauntlet.
Scott: Are you sure he can handle them all together?
Bruce: He could withstand Thanos' attacks with all of the stones when enraged. And he has trained himself throughout these years, making him stronger than he was before.
Thor: Thus making him the strongest Avenger from all of us.
Goku: *takes a deep breath and sighs* Let's do this.
Wanda: Please, be careful, Goku.
Goku: *smiles and kisses her forehead* I will, Wanda, don't worry.
Tony: Remember, Goku...everyone Thanos snapped away five years ago and just bringing them back to now, today. Don't change anything from the last five years.
Goku: Got it.
Everyone gets ready as Goku was warming himself up.
Tony: F.R.I.D.A.Y., do me a favor and activate Barn Door Protocol. Will you?
F.R.I.D.A.Y: Yes, boss.
Headquarters goes into lockdown mode as the door closes the facility.
Goku: Everyone...get ready to come back home.
Goku slowly moves his hand towards the gauntlet and puts it on as the nanobotically expands to fit his hand. He felt the power surge of the stones enters him as he grunts.
Wanda: Goku?!
Thor: Take it off! Take it off!
Goku: No!
Steve: Are you sure, son?!
Goku: Don't worry about me! I got it!
Soon, his aura flares out as he grunts and yells, charging up his power.
Goku: Super KaioKEEEEEENNN!
His aura and body turn a dark red as everyone had to grab onto something so they can fly off by the sheer power. Soon, Goku stops yelling, now fully in control as he looks at the gauntlet.
Goku: Sam...Pietro...Bucky...T'Challa...Lady Sif...everyone...welcome back!
Everyone was blinded by the flash of light as they covered their eyes. As it dies down, they look and see Goku standing there, still having the gauntlet in hand as he stares at it.
Wanda: Goku? Are you okay?
Goku: *looks at her* I'm...fine, Wanda. Guys...I can sense...everyone. It worked! It freaking worked!
Goku drops the gauntlet as he picks up Wanda and spins her around, laughing in joy as Wanda was startled by this. Scott looks outside as he sees the plants and birds as Clint gets a phone call...from Laura.
He picks it up and answers the call, as he struggles to speak as he was happy.
Clint: Honey...honey.
Goku was laughing in joy until he sensed danger as he puts Wanda. He looks up and sees a ship above them, firing a blast.
Goku: INCOMING!
Goku uses his Ki to shield everyone but himself as a barrage of blasts rained down on the compound, destroying it. Goku gets hit the most as he struggles to make sure everyone was safe as they sink until he couldn't hold it.
Goku lays underground, hurt by the barrage of blasts hitting him while everyone else was buried underneath the rumble, but unharmed, thanks to him.