Ostensibly picking up where the movie Buffy the Vampire Slayer left off, episode one finds the vampire-stiffing Buffy Summers (Sarah Michelle Gellar) and her mother, Joyce (Kristine Sutherland), recently moved from Los Angeles to the ironically named suburb of Sunnydale, CA. During her first day at Sunnydale High School, Buffy meets a group of people who will define the course of her new life. Cordelia Chase (Charisma Carpenter), a popular girl at school, proffers her friendship by testing Buffy's "coolness factor." "James Spader?" Cordelia inquires. "He needs to call me," replies Buffy, without missing a beat. But Cordelia is soon dismayed when Buffy begins hanging out with the shy computer nerd Willow Rosenberg (Alyson Hannigan), her friend Xander Harris ( Nicholas Brendon), and his buddy Jesse (Eric Balfour). Also among her new acquaintances is the school librarian, the very British Rupert Giles (Anthony Stewart Head), who just happens to be Buffy's Watcher, a sort of guidance counselor for vampire slayers. Giles informs Buffy that the earth is much older than commonly accepted and was once populated by demons and vampires; only vestiges of the great evil still exist. Through Giles, we also learn that after every slayer dies, another is born to take her place, and 17-year-old Buffy is the Chosen One. That night, Buffy meets the enigmatic and mysterious Angel (David Boreanaz), who warns her that Sunnydale is located on the Hellmouth -- a kind of mecca for demons and vampires of all sorts -- and the accompanying "Harvest," when vampires will attempt to take over the earth, is soon approaching. Buffy is resistant to donning her mantle as the Slayer, unaware that in catacombs beneath Sunnydale, the Master (Mark Metcalf) -- a very old and powerful vampire, trapped for 60 years underground -- is now being awakened by his minion Luke (Brian Thompson) to be set free by the Harvest. Originally aired on March 10, 1996, "Welcome to the Hellmouth" is part one of the show's two-part pilot episode.
by Matt Collar synopsis