Otherwise known as Amy-recs-a-Spuffy-fic.
The Bad Man, by db2305, is actually Spike/Buffy/Spike (yes, obviously the slash potential is what drew me in), and wowsa. Told from the POV of Insane-In-The-Basement Spike, who has a brief encounter with the future. It was the slashy aspect that drew me in, yeah, but the characterization that made me want to rec it. Basement!Spike and his reactions to his future self and future Buffy are alternately comforting and heartbreaking, and the story itself manages to be painful and hopeful at the same time. And, er. Hot.
[Disclaimer for those who haven't hung around here for the last 4 years: that's not a statement on the objective quality of any S/B fic, just an acknowledgement that I'm a slasher and my OTP is Spike/Xander, with Spike/Angel and/or Angel/Wes running a distant second; S/B is usually my pairing-of-anti-preference, both in canon and in fic.]