This is a world of vampires, demons and magic. Buffy Summers is the Vampire Slayer, a girl called to the task with great strength and powers of recovery. Rupert Giles is her Watcher, who guides her through the battles with the monsters. Sunnydale is the centre of the hell mouth and hence the source of many creatures of evil.
The first season introduces Buffy, her Watcher, Giles, her school friends, Willow and Xander and her mother Joyce. Cordelia is the school show-off. The main villain is The Master, an ancient vampire trapped underground. Angel is a vampire with a soul who appears and helps. Other characters introduced are Amy, The Annointed One, Jenny Calendar, Principal Snyder and Harmony.
The second season sees Buffy and Angel become close until Angel loses his soul and returns to his evil ways. The main villains are Spike and Drusilla.
The third season introduces a second Slayer, Faith. She eventually turns evil and teams up with the season's villain, the Mayor. The vengence demon, Anya is introduced.
In season four, Buffy goes to college and meets Riley. A secret government operation, the Initiative, captures demons and uses the parts to make Adam, a composite. Tara is introduced.
Season five sees the introduction of Dawn, Buffy's sister. Dawn is actually a key made of energy hidden on Earth and sought by the season's villain, the god, Glory.
Buffy's friend Willow develops her magical powers so much that she becomes too powerful to control.
Buffy, Faith and a number of potential Slayers fight The First, the ultimate and original evil.