A/N: The song from this story is "Rain in Soho" by The Mountain Goats.
When Bucky reappeared after the Snap, it took two hours to debrief him, but mostly because Steve wouldn't let go.
His actual debrief was four words, "Fuck if I know."
It was what Coulson called, "succinct" and Bucky himself called, "About as helpful as cupping a corpse." Steve knew it was a Yiddish idiom, but that led to a whole new series of questions, including how long Bucky had been Jewish, and what exactly went on when his people sat Shiva.
They went to see Clem. He was a friend of Nat's, something about "kitten poker," but T'Challa was visiting so they didn't let her elaborate. Clem introduced them to a friend of his from the set of Britain's Got Talent.
Sweet wore a zoot suit, which made Steve and Bucky feel more comfortable. He was a demon that could reveal hidden truths by making people sing about their feelings, which did not.
Sweet took them to a bar in the old Bowery Poetry Club. It was closed, but he unlocked it with a skeleton key and led them past brick walls so infused with beer that they smelled like loaves of bread. They sat on folding chairs in a small room. Tony stopped to pour himself a drink from the bar, so he had to sit on the floor.
There wasn't a stage, just a space in the middle, empty except for a piano and a microphone. Sweet swept his zoot suit coat behind him with a flourish and sat down at the piano bench. He gave Bucky, "and a one, and a two, and-"
Bucky began to sing.
[CENSORED]
Sweet left them with the job of interpreting the song and locking up on their way out.
"Lone wolf has to be Barnes, right?" said Sam. "White Wolf. Howling Commando. There's a theme here."
"I think he is more like your Grumpy Cat," said T'Challa.
"It's true," said Steve. "You have nine lives, and I'm pretty sure you carried me away from a fight by the scruff of my neck once."
"I don't land on my feet," said Bucky.
"Too soon."
"It's been seventy years, Steve."
"Too soon."
"But what's the hidden treasure in the castle keep?" asked Sam.
"Um, I think that's also Bucky." Steve was blushing. "Because we've been keeping him hidden in the tower-"
"-Just in case the government is still on The Hunt for Red October." Tony was lying on the piano now that it was unoccupied. "Yeah, yeah. It's all about Barnes. All that stuff about how there's no greater love than to lay your life down for a friend. Oh, no. I wasn't going to cry."
There was a sound like a whoopie cushion being let out an airlock that somehow originated from Tony's nose.
"For fuck's sake, Tony," said Steve. He scootched over so Bucky could share his folding chair.
Tony took another drink and only spilled most of it. "The bit about the Batcave closing must be about Steve… Steve's Batcave. Oh, Stevie, are you not putting out anymore?"
"For the sake of the fucks, Tony," said Thor. "That is their business."
"I think I got it," said Bucky. "It's at the end. No sweeter pleasure than to see the credits clear through to the end. There's another universe where all of our lives are just movies. There's no such thing as aliens, or gods, or super soldier serums, or anything."
"That sounds fake, but okay," said Scott.
"How do you know that?" asked Fury, and Steve wondered how long he'd been there, but he knew better than to ask, because Fury's stock answer was, "...Long enough."
"Hydra gave me multidimensional space time travel using Tesseract technology and no sense of causality so I could kill Steve in other dimensions, but I ended up in the movie dimension, and Chris Evans has a lot of dogs."
"Chris Evans?"
"He plays you."
Steve felt a little affronted by this even though a lot of people had played him. "Who plays you?"
"Sebastian Stan."
"Sebastian?" Tony giggled. "That's worse than Bucky."
"I like Bucky," said Steve.
"We noticed," said Sam. "You're probably the one who saddled him with that nickname in the first place."
"Actually, it was Becca," said Bucky. "My baby sister. She couldn't pronounce Buchanan."
"Question: Why wasn't she calling you James?"
This time, Steve giggled. "His Ma middle-named him so often that Becs thought it was part of his first name."
"Like you got in trouble less? You got in a fight every day of the week, pal."
"I was protecting people from bullies."
"You were giving the bullies a new target. Only bright side is that they couldn't make your ugly mug any uglier."
"Look who's talking. No wonder Hydra covered your face."
"Well, I can only see your old one. It's like your ears and nose always knew you'd be huge."
"Feet too," Steve said helpfully.
"Enough flirting," said Tony. "So the multiverse theory is correct?"
Bucky made the "I dunno'" noise. "There isn't a universe for every possibility, at least as not as far as I can tell. Just a few. Like different retcons of the same comic. There was one where we were all working in a coffee shop. Another one where we're all in high school."
"Weird," said Tony, Nat, Steve, Clint, and for some reason, Coulson.
Bucky clapped his hands, which looked like it hurt. "So we can defeat Thanos by going to the dimension where our lives are movies and watching how they defeat Thanos. Sure, that one's not out yet, but there are always copies on The Dark Web."
Steve raised his hand, jostling Bucky slightly. "What's the Dark Web?"
"My time to shine," said Tony. "The dark web is a part of the internet that exists on an encrypted network. You need special software to access it. That's technically legal, in a read-the-fine-font sort of way. The websites that exist on it are not. You can buy anything on the Silk Road with enough digitally laundered currency. You remember that girl who sold her kidney to buy an iPhone? Then she found out that wouldn't be enough and tried to sell the other one? Oh. Well, the cops got there just in time. Anyway, she sold it on the Silk Road. It's always harvest season on the internet. People who view this item also viewed drugs, guns, and kiddie porn. You can even hire an assassin. Deadpool will make it look like an accident for anyone who refers a friend. You've probably never heard of him, but he's totally dark net Famous. No, Steve, we aren't hiring Deadpool. He only has two stars."
Steve lowered his hand.
"So how do you travel to this alternate dimension?" asked Fury.
Bucky sighed and wiggled his nose. A second later, Steve's lap was empty.
Three hours and one minute later, Bucky reappeared in Steve's lap. The Avengers had spent that time comforting Steve. He was from the forties, so they mostly did this by slugging him in the shoulder. Bucky however, appeared unharmed, although his breath smelled faintly of Orville Redenbacher.
"Well?" asked Fury.
"Well… Good news. If we kill Thanos, everyone should reappear who disappeared during the Snap. They're just in another dimension. That's why I was able to escape."
"Bad news?" asked Fury.
Bucky appeared to be steeling himself, which was concerning, since he was already 12% steel. "The way they killed Thanos in Avengers: Endgame was by sending someone wearing the Antman suit up his butt and then getting really big, really fast."
Tony started gagging.
"You're very queasy for someone named Ironman," Bucky observed.
Tony sat up. "No, I just swallowed wrong."
Scott appeared to steel himself as well. "Thanos took my family away from me. I'll do whatever it takes to get them back. This world may not be perfect, but it's-"
"Sorry to steal your thunder," said Bucky, "but it's gotta' be me. I'm the only one who's seen the CGI version of an alien butthole. I'm the only one who knows the pressure point that can kill Thanos."
"Is it the-"
"Don't ask questions you don't want answers, Stark." Bucky didn't so much say it as intone it.
Tony considered that and then actually shut his mouth.
"Besides." Bucky shrugged. "I lived with Hydra for seventy years. I'm used to assholes."