When She Was Bad
Original air date: September 15, 1997
Buffy returns to Sunnydale after spending the summer in LA, she is distant and has an attitude towards her friends. While being away, she has realized she will never be a normal girl, that being the slayer will always be her life. When Buffy learns that the vampires are preparing to use the Master's bones to ressurrect him, she must stop them.
When Willow, Giles and Jenny Calendar are taken by the vampires, Xander tells Buffy that if anything happens to Willow, he'll kill her. We see that even  though he may have a crush on Buffy, Willow will always be the one he will care about.
This was a really good episode even if Buffy's attitude was a bit disturbing. The scene at the end where her friends watch as she destroys the Master's bones in a rage makes them realize just how hard being the slayer must be for her. Buffy has been hiding her fears of the Master the whole episode, but at the end, she breaks down in tears as Angel holds her. This episode marked the very beginning of what was going to be one of the greatest season of the series.