I'll add notes when I re-watch this series.
A highschool cheerleader, learning she is imbued with the spirit of the Vampire Slayer and her school was built on a Hellmouth, is trained by an ancient order of Watchers to fight vampires and other monsters from ending the world.
An astonishing series, and I don't say that lightly. The characters and story are outstanding. While this is a fast-and-loose show, it matures. It spinoff/partner series, Angel (1999-2004) is even more adult. This show is well worth the time, even if its initial episodes put the viewer off with its childishness. It's not a series that "grows on you", it really does get better and better, building upon and maturing out of its initial impressions.
- Based on Buffy the Vampire Slayer (film), which is neither mandatory nor recommended viewing.
See also Angel (1999-2004), which is set in this universe and shares significant-enough elements that crossover-viewing is largely considered mandatory. See Buffy the Vampire Slayer and Angel viewing order.