Short summary: Buffy escapes evil Luke, emancipates all (except Jesse) from enemies. Willow and Xander now experience the evils and get to know the esoteric expert Giles, while Buffy meets the enigmatic Angel again. Buffy endangers herself (and escorts Xander) when she goes to the underground enclave of the egregious Master; and finds that Jesse is now an excrable vampire. They escape and figure out the Harvest (some evil equinox) is here and through an extrasensory Vessel, the Master may find egress from his ensorcelled enclave. She puts an excellent end to this at the exalted Bronze. Then Buffy and friends eloquently entreat about a mall establishment. "The world is definitely doomed."
Analysis: Awesome. While the first episode started off at a good pace, but had some strange moments, this episode firmly cements the show as awesome. On the whole, the episode is pretty simple: Buffy goes places, is attacked by vampires, goes other places, is attacked by more vampires, and at the end kills the biggest vampire and wins. But underneath the thin veneer of simplicity lies a much more complex metaphor: the Master and his Vessel Luke, like father and son. The Master wishes to escape by feeding (living, practically) through Luke (a theme repeated again in the next episode, "The Witch"). Meanwhile, Buffy and her mom are having trouble themselves - in one of the best scenes, Joyce grounds Buffy for the same behavior that got her kicked out from her previous school. Buffy, saddened by this, simply escapes out the window.
The fact that the climax of the episode takes place in the Bronze means something too (and not just that they didn't have many sets). The Bronze has been shown as a place for teenagers, so naturally Luke (The Son) would go there, to sow his wild oats. With some symmetry, in the very last episode of the season, Buffy believes the Hellmouth will open at the Bronze, but is proven wrong when it opens in the library - because then it is the Master himself (the Father), who is more about knowledge than freedom.
Note: the DVD I'm watching was bought used, so parts of the episode skipped. While I've seen the episode enough times to practically know all the lines, it was still pretty weird.