It starts with Clint discovering Barney and the Swordsman's (probably?) shady businesses and confronting them. They beat him up, Clint gets seriously wounded and ends up in hospital, the circus (where he was still working at the time) leaves him behind. Clint has no money to pay the bills and flees from the hospital as soon as he is able to. He ends up on the streets, and he soon starts prostituting himself. The pimp that rules the area forces Clint to work for him, taking most of Clints money for "protection". Clint still has hopes to escape one day (he regularly goes to the local library to read), and I think he sneakily saved some money, but the day he attempts to leave, the pimp catches him and brutally punishes Clint (Clint gets gangraped and I'm pretty sure the pimp mutilates him somehow. Or maybe he threats mutilation? It's really, really brutal either way. Poor Clint...). Clint is pretty much broken after this.
I seem to remember Clint getting saved by Natasha somehow (she comes to murder the pimp or one Clint's customers, Clint witnesses the whole thing, but isn't afraid of her, because he'd welcome death at this point or something?), and then he eventually ends up with SHIELD (Natasha frees him and takes him with her?), and they know him his Hawkeye days and want him to work for them. I do remember Clint telling Coulson that he has debts from the hospital, and that Clint has some major issues to overcome, but I couldn't even say if it's Clint/Coulson in the end.
I'm starting to fear this story has been deleted (because I was so sure I had it saved on AO3...), so I'd be ridiculously grateful if, in case it really was deleted, someone has a copy to share with me!
Thanks in advance!
FOUND! Link in the comments!