Y/n has been dating Steve for the last nine or so months. Things are just starting to get serious in their relationship - they know each others coffee orders by heart, their circle of friends is starting to overlap and they’ve even just moved in together - when Steve abruptly goes under the radar to track down his war time bestie, Bucky Barnes. One long mission later, he’s back at the apartment he shares with y/n, this time with the Winter Soldier in tow. And okay, having an ex-Russian spy slash mercenary recovering from mind control slash PTSD in your guest bedroom isn’t exactly ideal. But y/n tells herself she can deal. Maybe. Eventual y/n x Bucky Barnes x Steve Rogers