...the Chosen One...
...she alone can stand against the vampires, the demons, and the forces of darkness...
Yes, that's right...
Buffy Summers is the Vampire Slayer.
Buffy Anne Summers, the daughter of Joyce and Hank Summers, was born in January, 1981. Most of her childhood was uneventful and gave no indication of the future that lay ahead of her. However, in 1996, Buffy, a student at Hemery High School in Los Angeles, was informed by Merrick, a "Watcher", that she was the "Chosen One".
As the Slayer, Buffy discovered that she possessed superpowers such as extraordinary strength and the ability to heal quickly. Under Merrick's supervision, she trained to use these powers to fight and kill vampires. However, in the course of her battles, Buffy burned down the gymnasium at her high school, leading to her expulsion. Buffy and Joyce, who had recently finalized her divorce from Hank, moved to Sunnydale.
At Sunnydale High School, Buffy, then a sophomore, met her new Watcher, Rupert Giles. Together with her friends, Willow Rosenberg and Xander Harris, Buffy continued her fight against evil. And there certainly was plenty of evil... Sunnydale, located over a Hellmouth, is a center of demonic activity and appears to be a magnet for vampires and demons of all kinds.
Soon after moving to Sunnydale, Buffy met Angel, a vampire with a soul. He helped her with her battles, and they eventually became romantically involved. Together, they faced Buffy's first real enemy, the Master. A very old and powerful vampire, the Master had been trapped beneath Sunnydale and hoped to regain his powers in a ceremony that would open the Hellmouth and release Hell onto Earth. While fighting him, Buffy died briefly. Although she was quickly resuscitated by Xander, Buffy's momentary death was enough for the magic to call a new Slayer, Kendra. The full story of Buffy's battle with the Master is chronicled in Season 1 of the television show Buffy the Vampire Slayer, and Buffy's death is detailed in the episode Prophecy Girl.
The continuing story of Buffy's life and adventures is best told by the television show about her. Summaries of many episodes are available at the Buffy the Vampire Slayer Episode Guide. The show itself is currently in its sixth season and airs on UPN in the United States. It is also in syndication on FX, so you can catch all the episodes you missed.
Oh yes, in case it wasn't obvious, Buffy Summers is a fictional character, created by Joss Whedon.