Hello! sorry for my bad English, I'm ESL! I'm looking for a old one, circa season six, when the little dirty secret affaire is on. I remember that Buffy and Spike are in a fight with a group of vampires/demons and Spike is dusted with sunlight; Buffy is shocked and hurting but she have a talisman o something and with that repeat the day, preventing Spike's death.

I am a bit thrown with the dusted by sunlight bit. They were fighting a bunch of vampires in daylight?

There is a fic where he's dusted while they are fighting a couple of vampires and Buffy gets Willow to do a spell. Maybe this is the fic:

Regrets....I Had a Few by Schehrezade