HP: A Thousand Doors by Kest (Sirius/Remus)
I think kestrelsan was the perfect writer for this story: the aftermath of Regulus Black's death. A Thousand Doors is achingly sad, even more so because Kest's moody, atmospheric prose still has a wise sort of restraint about it. The emotions underlying the story are dark and guilt-ridden and frightening, but their impact is due to the fact that they mostly remain unspoken.