Buffy the Vampire Slayer (1997)

After moving in hopes of leaving behind her duties as a Slayer, Buffy inevitably reconnects with her Watcher, the librarian Rupert Giles, and the two friends join forces to battle demons side by side throughout the series. They soon realize that Sunnydale High is situated atop the Hellmouth, a portal to demon dimensions that attracts supernatural phenomena to the area.