There are a couple of new vampires in town: Spike and Drusilla. The former is a rebellious sort who goes his own way rather than stick with the traditional vampire rituals; the latter is the love of his life, who is completely insane and very weak. The show up in time for the festival of St. Vigeous, when vampires' powers are at their height. Before that, though, is a much greater horror for Buffy: Parent-Teacher Night, and she's scared to death of what her teachers (not to mention the misanthropic Principal Snyder) will say to her mother. However, Spike - a.k.a. William the Bloody - decides to jump the gun and attack the school on Parent-Teacher Night, tow nights prior to St. Vigeous.
Buffy manages to drive them all off, with some help from Angel, Xander, and at the end, her mother, who clubs Spike with a fire ax. Spike runs off, and is then soundly criticised by the ANointed One and his cronies. Spike replies by throwing the ANointed One in a cage and exposing the boy to sunlight, then going to watch TV with Dru.