April 15, 2003
Dirty Girls aired for BTVS season 7, episode 18. This was the return of Faith to BTVS. Willow brought her back from LA after ATS 4x15 Orpheus.
This is the first appearance of Caleb, who would continue to appear in all (4) remaining episodes. Caleb is played by Nathan Fillion. This is also the first time that Faith and Spike meet when they look like themselves. Faith remembers meeting Spike before in S4, but Spike is not aware that he previously met Faith when she looked different. They have memorable conversations in the cemetery and Buffy's house's basement.
(This is also the first time that we see Faith and Dawn interact, but because of the monks they both remember each other from before.)
This episode also includes the only appearance of a Vulcan in the Buffyverse. (The most famous Vulcan is Spock from Star Trek.) As Andrew shares a story we see it as a flashback, with Faith fighting a Vulcan. Andrew thinks Faith killed a Vulcanologist, meaning a person who studies Vulcans. (For some reason in his flashback we see an actual Vulcan including pointy ears. It does not appear to be a person in cosplay.) Actually Faith killed a volcanologist, a person who studies volcanoes. The Potentials correct Andrew on his mistake, but not before Faith gets the upper hand on the Vulcan in his flashback.