During a field trip to Sunnydale Zoo, a gang of students enter the off-limits hyena enclosure, followed by Xander. The hyenas' spirits possess the students who begin exhibiting cruel animalistic behaviour on their return to school.
They pick on the defenceless; kidnap and devour the school's mascot (a pig named Herbert); and attack and kill the school Principal. Buffy and Willow notice the change in Xander's behaviour, and investigate. They discover that the zookeeper (James Stephens) is behind a plot to harness the supernatural power of the hyena pack. But Buffy manages to turn the tables and the pack turn on their leader, the zookeeper. "It shouldn't be too hard to find a new Principal" muses Buffy "unless they ask what happened to the last one..."
