It’s season 5, and quite honestly one of my favourite buffy episodes. It’s the one with “the Gentlemen” in it.
It’s Hush, in the fourth season.
Season 4, episode 10, “Hush”
I can’t remember the episode but it’s in the fourth season cause they’re in college.
I WONDER WHAT SEASON THIS IS IN. I’m on the second season now, I’m pretty bad at getting obsessed with shows though.