I think it's post-NFA. L.A. is sort of a demilitarized zone. Angel lost his soul and has taken over the city. Illyria and a badly injured Spike are found by Xander, Dawn, and 3 slayers. One of the slayers is a bad girl hankering after Xander - I think her name is Charly. Another is an explosives expert. Everyone hunkers down together in a warehouse and Xander hooks up water, etc.
Spike and Xander fall in love gradually. Charly goes bad and sides with Angel and there's some magic books involved. I hope that's enough. I seem to be able to remember storylines and characters better than titles and authors, apparently!
Thanks for your help.
