If you�ve ever stopped to ponder the ethics of what Buffy does - slaying sentient beings, and even the occasional detour into genocide - then Bad Girls should give you plenty of food for thought. Throughout this episode Buffy fails to recognise the warning signs being broadcast by Faith, (discussions about how killing gives her a thrill - "tell me you don�t get off on this" - and her reckless attack on Balthazar�s El Eliminati acolytes), eventually resulting in the death of Alan, the deputy mayor.

His death, a tragic accident that Faith initially seems very disturbed about, is the catalyst that finally allows her to shed her last vestiges of responsibility. What's more tantalising is that Buffy very nearly follows her, a point well made by author Douglas Petrie in what�s essentially the first part of a two-episode story. Had Alan not died, how long would it have been before Buffy was just like Faith?

Alan�s death is a very powerful scene, and one that signals a fundamental change to a more mature series. With such an important A-story, it�s surprising that the Balthazar plot is not underdeveloped, partly because it allows space for the introduction of Wesley, the na�ve new Watcher. Alexis Denisof�s scenes with Anthony Stewart Head provide wonderful counterpoint to the more grisly aspects of the drama.