I don't remember too much but I'm pretty sure it was Steve/Bucky or gen, and I think Sam was a character in it. I don't think it was very long, pretty sure it was on AO3. I have tried looking through the whole zombie tag on AO3, and some fic rec sites but didn't have any luck.
Any help is appreciated:)
FOUND by dhrachth - crawl home by bibilonerd07