Basically, what the title says- there's a dance contest for money. Buffy is the slayer and Spike is a vamp in this fic, so no All Human. If I remember it correctly, Spike caught her practicing her dance moves in the training room at the Magic Box, and got a bit snarky like Spike tends to do. I think it might have been S5 though I could be wrong. Still, I'm fairly certain they weren't friendly in the beginning of the fic, but Spike has convinced her to let him help her out since he knew various dancing styles. He said he could use the money. It was a long fic and I remember the dance moves were really well described. Also, I think Spike had to trade his boots for dance shoes because he couldn't move as well. Buffy didn't tell her friends about the contest and as she and Spike practiced together, they got closer.
I've read it a long time ago. It's been bugging me for a while, and I haven't found anyone asking about it on the forum, so I really hope this sparks someone's memory.
