Old and new friends gather at the Summers home for Buffy's 21st birthday party and it goes off without a hitch - mostly. Feeling neglected by Buffy and the Scoobys, Dawn's wish to keep people from leaving her is answered by Anya's demon friend Halfrek, who binds the attendees of the party to the house. When Tara tries a spell to free them, she only makes the situation worse by accidentally releasing a demon trapped inside a sword.
"Into every generation, there is a chosen one. She alone will stand against the vampires, the demons, and the forces of darkness. She is the slayer".
When a young vampire slayer by the name of Buffy Summers, moves to Sunnydale, California, she quickly finds out that Sunnydale is located right on top of the Hellmouth - the center for all evil activity. Her new watcher, Rupert Giles, also happens to be the school librarian. It is his job to train her and guide her in all the skills she needs to be a Slayer. She and a group of close friends, commonly referred to as "The Scooby Gang", help her in her battle against evil.