Steve, Bucky, and Nat are the last ones left

[ladyhatshepsut.livejournal.com]

I've downloaded and read 2 or 3 of these, then found another one and promptly missplaced it and I can't remember if I downloaded it or not.  So I'm going to ask for any stories with this theme.  Because of their exposure to different versions of the super soldier serum, Steve Rogers, Bucky Barnes, and Natasha Romanov age very slowly and live quite a lot longer than the rest of the team.  For whatever reason they form a close triad.  (In one story Steve is part of the triad even though he is asexual.)  (In a pair of stories where charmingcontender re-wrote and expanded the same story for take two, Steve and Bucky are on the run from the US governement for the Winter Soldier's war crimes against the State and Widow joins them for several decades while the rest of the team help them escape and protect them.)  The stories end with everyone else passed on from old age, and Steve and Bucky (and maybe Nat) aging very slowly if at all and going on decade after decade together.

All I recall about the one I lost before I could read it is it ended with the last two (Buck and Nat?  Steve and Bucky?) kissing and one or both disappearing.  Ring any bells?