The secrets of Giles' unnatural past as a wild teenager are revealed when an old friend of his comes to warn him that a demon that they both summoned has returned. As a young man, Giles turned in his Watcher studies in favour of dabbling in witchcraft and the occult with his old buddy Ethan Rayne and several others. They discovered Eyghon The Sleepwalker and summoned him while one went into a deep sleep. Unfortunately, Eyghon gained power by this andhuged them all one by one over the years by possessing a dead or unconscious person and is now after the last two members, Giles and Ethan.
"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.