Dark!Willow antagonist

This may be a long shot, as I don't have much to go on. Looking for a fic in which Dark!Willow is the antagonist, and she's amassed a lot of power over a period of time.

She now rules over many (all?) creatures of the night, and Spike may be a double agent whose true allegiance is to Buffy.

One scene I remember clearly is Buffy and Spike doing a spell that transports them to a house just outside Sunnydale. This spell might also involve time travel. Either way, its purpose is to send Buffy and Spike somewhere that Willow can't detect or harm them.

If anyone is supersleuth enough to name this fic based on these few clues, I bow to you with a courtly flourish.

I remember reading a story that sorta sounds like this. I think I read it on the bloodshedverse. Willow was the evil leader of Sunnydale and Spike was under her control even though he really opposed her. I remember she could call anyone to her instantly no matter where they where. I think buffy was somehow pulled into this alternate reality so she was shocked by what was happening and tried to fight Willow. She turned to Spike for help. I remember Spike took her to see Jenny Calendar who was one of the only people who could fight Willow. I'm trying to remember the name but does this sound remotely like what you are talking about?

Yes! Yes! That's the very one. Thanks for the great summary. Hopefully someone can ID it.

Future Sins Past by dreamsofspike ??

Willow is vamped about halfway through (definitely appears about Chap30) and creates this alternate sd spell where she is in control. I think, if I'm remembering right, Spike was enslaved to her but trying to help Buffy break the spell with Jenny in hiding.

Thank you! That's the one

Awesome! Glad you found it!