Okay so, once upon a time Steve’s mother moved to a seaside town with him, because the air was supposed to be better for his lungs. And Steve becomes best friends with Bucky because obviously. And Bucky teaches him how to swim and how to tie knots and even takes him fishing out on the sea a few times and tells him stories of mermaids and sea monsters while Steve draws and then freaks out because HIS ROD IS MOVING BUCK WHAT AM I SUPPOSED TO DO NOW?
And then they grow up and Bucky joins the Navy because it will give him enough money to take care of his family and also Steve, who tries to join as well and basically gets laughed out of the recruitment office.
So Bucky goes off to be dashing in his uniform and he writes Steve letters… only then the letters stop coming. And then Bucky’s family gets a letter that their son’s ship has been lost at sea. But Steve refuses to believe his best friend is dead and he KNOWS where Bucky disappeared and if he can just GO THERE. But none of the ships will take him and he pretty much goes ‘fuck all y’all’ and makes his way to a known pirate port by land and by being a stubborn little shit and when he pretty much finds that pirates also go ‘lol no’ at skinny wheezy runts who want to join their crew, he just sneaks on one of the boats.
And that is how first mate Sam finds Steve hidden behind some barrels or some cliché and he takes him up to Captain Natasha and she’s all: eh, he’s feisty and he probably doesn’t eat much, let’s keep him. (It’s probably how she got Clint as well.)
And Steve learns to be a pirate and learns ship stuff and also grows a little tanner and stronger and less sick and gains respect from the crew of The Widow. Clint teaches him about the rigging and Sam teaches him first aid and Thor and Natasha teach him how to fight.
And then they get near where Bucky disappeared and there’s no sign of him and Steve is VERY SAD and kind of gives up. But he stays on The Widow because well, where else would he go? And they go on being badass pirates and there are adventures and then they run into another pirate ship that turns on them, and Steve is like ‘wtf pirate code?’ and Clint is like: Um yeah the Captain has a grudge against Hydra and they have an even bigger grudge against her.
And then there’s FIGHTS and the crew of the Hydra boards and there’s swordfights and Steve uses his tininess to his advantage like Natasha taught him… until he comes up against this guy with long hair and an odd arm with a hook at the end and…
“Who the hell is Bucky?”
And then Thor knocks him out like TINY STEVE, THAT IS NOT HOW YOU FIGHT AGAINST YOUR ENEMY and they manage to drive off Hydra and Steve manages to convince Nat to keep Bucky as a prisoner.
And Steve visits Bucky down in the brig every day and talks to him for hours and the crew is worried but he won’t give up on Bucky. And Sam and Clint are all: Nat, can’t you talk to him or do something? And Natasha just lets Steve do his thing.
And then Bucky starts getting his memories back and Steve slowly pieces together what happened to him. And Natasha is all: yeah the same thing happened to me, way to go on breaking the brainwashing, Steve, it took me years and years to come back to myself.
And then they cheerfully go on their way to destroy Hydra and save any other victims and bring down the land-lover business man who secretly controls the Hydra pirate ship. He was attacking other traders and shit to grow power of his company SHIELD. And when he’s taken down, this guy called Nicholas Fury takes over and there’s rumours he may have been a pirate and he WEARS AN EYEPATCH FOR GOD’S SAKE but nobody mentions it because hey, he’s doing more good in the world than Pierce ever did, maybe-former-pirate or not.
And all the while they’re taking down Pierce and Hydra, Steve and Bucky get reacquainted and are grossly sappy and Clint has taken to flicking things at them from the crow’s nest when they sneak on deck in the middle of the night to make out.
AND THEN THEY SAIL OFF INTO THE SUNSET and eventually retire somewhere with their loot and they go fishing and Steve loses so many fish because he’s too busy drawing and they sometimes get visits by Natasha and Sam and Clint and Thor and the rest of the crew.