(The next day)

Y/N's P.O.V

Yelena and I are in bed cuddling and she looks down at the ring on her finger.

Yelena: I still can't believe how beautiful this ring is. Where'd you get it from?

I smile.

Y/N: My mum gave it to me. It's been in my family since the 1940s. My great-grandfather gave it to my great-grandmother. It's actually a really nice story.

She looks up at me.

Yelena: Can I hear it?

I smile.

Y/N: Sure. My great-grandfather fought in WW2 and when he was stationed in London he bought this ring as he planned on proposing to my great-grandmother. He fought all the through Europe with this ring wrapped around his neck with his dogtages. Then after thirteen months he came back to New York and my great-grandmother was waiting for him at the port, when they reunited he proposed on the spot.

Yelena: That sounds amazing and romantic.

Y/N: Yeah, it was. My great-grandmother gave it to my grandfather to give to my grandmother, then my grandmother gave it to my father to give it to my mother and my mother gave it to me to give to you.

Yelena: So, if we have a son that means I have to give it away too?

I chuckle.

Y/N: I guess so. We'll cross that bridge when we get to it babe.

After another hour or so we get up and head into New York to see my mum.

(Three hours later)

After visiting my mum for a bit we head to the Compound to see Nat and tell her how last night went.

Natasha: I still can't get over the how beautiful that ring is. Y/N, your great-grandfather had amazing taste.

I chuckle.

Y/N: Thanks.

After talking for a bit longer Nat has a quick meeting with the other Avengers that are both on earth and in space. Then we get a visit from Cap. He congratulates Yelena and I on our engagement, then Nat looks to him.

Steve: You know I'd offer to cook dinner, but Nat already seems depressed enough.

I smile.

Y/N: You here to do your laundry?

Steve: And to see some friends.

Natasha: Well, your friends is fine.

As we all continue to talk an alarm goes off.

We see security camera footage of the front door and see Scott Lang a.k.a Ant-Man standing there.

Steve: Is this old footage?

Natasha: No, it's the front gate.

Once we get Scott inside he starts pacing around.

Yelena: Scott, are you okay?

Scott: Yeah, yeah it's just... have any of you studied quantum theory?

We all look at each other.

Y/N: A little bit.

Natasha: Only to make conversation.

Lang goes on to explain that before Thanos showed up that he was in a place called the quantum realm. And that he was there for three hours, even though for us it was three years.

He then says that there could be a way to use the quantum realm to travel through time.

Y/N: Wait Scott are you talking about building a time machine?

Scott: No, no not a time machine. Well, I guess yeah a time machine. I know it's crazy.

Natasha: Scott, I get emails from a talking racoon. Nothing sounds crazy to me anymore.

Steve looks at me.

Steve: Y/N, could you do that? Could you build a time machine? I mean I know you're retired and all but...

I interrupt him.

Y/N: I could, but I'd definitely need help. I'd need someone with a really big brain. I mean I'm a smart guy Steve but quantum physics isn't exactly in my wheel house.

Yelena and I look to each other, then to the other's.

Yelena: Guys. Can Y/N and I have a moment alone?

Steve immediately knew what this could be about and nods.

Steve: Sure. Come on guys.

Nat, Steve and Scott leave the room.

Y/N: So, what do you think?

Yelana: I don't know. I mean if this can bring everyone back maybe we should do it.

Y/N: Yeah, I agree. It's just that we agreed to leave this life behind. But if I'm being honest, I've missed it. I've missed being here.

I sigh.

Y/N: I've missed being Spider-Man and being an Avenger. But look if you're not 100% sure about doing this then we won't. It's your call.

Yelana looks down for a moment, she looks at me again.

Yelena: I think we need to do this. If there's a chance we can bring our friends back, bring everyone back then we need to help.

Y/N: Okay. So, one last mission for old times sake?

She smirks.

Yelena: One last mission.

(Two days later)

So a couple of days ago we went to visit Tony, but he didn't want to help as he didn't want to risk losing his daughter.

We then went to Bruce who has now combined himself with the Hulk and he's agreed to help me. The two of us used Scott's van to build a time machine for a test run.

But it didn't work as it just turned Scott into younger and older versions of himself. My theory is that we pushed time through Lang instead of pushing him through time.

I'm now outside with Steve as he left the room after thr failed test run.

Y/N: We'll figure it out Cap.

Steve: I hope so Y/N.

The two of us then see a car coming towards us. The driver pulls over, the window rolls down to reveal Tony.

Tony: Why the long face? Let me guess he tuned into a baby?

Y/N: Yeah, he did.

Steve: How'd you know?

Tony: It's the EPR paradox, instead of pushing Lang through time it pushed time through Lang.

Y/N: That was theory actually.

Tony: Someone could have warned you about it.

Steve: You did.

Tony: Oh I did, well it's a good thing I'm here then.

Tony shows us the time travel device he built.

Tony: Look we've got a shot at getting these stones but I have to tell you guys my priorities. Bring back what we lost, yes I hope so. Keep what I found I have to at all costs. And maybe not die while doing it would be nice.

Steve: Sounds like a deal.

Y/N: Yeah it does.

Steve and I both shake hands with Tony.

Tony then goes over to the trunk and gives Steve his shield back.

Steve: Tony, I don't know.

Tony: Why? He made it for you. Plus I have to get it outta the house before Morgan takes it sledging.

Steve: Thank you Tony.

Tony: Will you guys keep that quiet, I didn't bring much for the whole team. We are getting a whole team right?

Y/N: Yeah, we're working on that.

We then head inside and get to work.

(The next day)

Third person prospective

Scott Lang is sitting outside and see a space ship fly in and Nebula and Rocket exit it.

Rocket: Hey man, where's big green?

Scott: In the kitchen I think.

Lang looks to Nebula.

Scott: Cool space ship.

Nebula: Justin, Rhodey, Isaac. Be careful on re-entry there's an idiot in the landing zone.

Rhodey lands infront of Scott scaring him in the process.

Rhodey: What's up regular sized man?

Rhodes walks into the Compound.

Justin and Isaac web zip in and land down after Rhodes. The two then enter the Compound.

Bruce comes out and go over to the ship and leave with Rocket to go and get Thor.

Whilst that's going on Natasha and Yelena leave to track down Clint.

Y/N and Tony stay at the Compound and continue working on the time machine.

Now everyone gets ready to bring back the people they lost.