Buffy is losing her powers as a Slayer and confronts Giles about this.  Giles tells her that he will research it but instead he is the one causing it by giving her a drug.  Come to find out, the Watcher Society puts all of the Slayers through a test on their 18th birthday to determine if they are fit to continue in their duties.  Things go wrong when the vampire that Buffy is to confront breaks out and kidnaps her mother.