Not to give much away, but it was definitely Spike/Xander. There was a spell that ended up sending Xander back into time and meeting up with Spike and Dru and he's turned around then, becomes Spike's childe/lover.
But I think he's killed at some point, so that's why Spike really goes to Sunnydale. To have the spell done again that will send Xander back in time so they meet again and prevent his death, and Xander's name is kept out of the history books to prevent any of the Scoobies from remembering/figuring it out.
I honestly can't remember how it ends, but I remember it was really incredible reading.
Anyone have any clue?
It said Spander fic searches were allowed, so I hope I've done this right. Full apologies to the mods if I goofed but I know that's what the main focus was.
Thank you in advance for any help at all.