Joyce is hanging up a Nigerian mask given by a gallery friend when Buffy finishes unpacking. She reluctantly allows Buffy to go to find her friends, who are coordinating a vampire hunt via walkie-talkies. They are surprised by one another after Buffy runs into first Xander and then a vampire. After a fight where the gang tries to fight the vampire but gets beaten, Buffy stakes it. At Giles' apartment, Buffy avoids most questions about her summer, while Giles hides his emotions in the kitchen.
The next day, Joyce takes Buffy to see Principal Snyder, who takes vindictive pleasure in keeping Buffy from re-entering Sunnydale High. Joyce then drops off Buffy at a coffee shop for a scheduled meeting with Willow, who does not show up. She goes home and meets Pat, a book club member of Joyce's who does not hesitate to comment about Buffy's recent behavior and its impact on Joyce. While fetching fancy company plates for a dinner with her friends, Buffy finds a dead cat. Buffy and Joyce bury it, but that night, the Nigerian mask's eye sockets glow red and the dead cat crawls its way out of the earth.
Buffy has a nightmare involving Angel. When she wakes, the dead cat surprises her in the kitchen. Giles arrives to remove it in a cage. He notices the mask before leaving for the library, informing Buffy that she is not allowed on school grounds. At school, Buffy's friends decide to throw a big party. Giles is distracted by the discussion from a page showing Joyce's mask.
Dingoes Ate My Baby soon arrives at Buffy's house without notice. Overwhelmed by dozens of guests she does not know, Buffy tries to talk to a distracted Willow, but gives up. Xander and Cordelia are too busy kissing to care. Meanwhile, Joyce is telling Pat in the kitchen how tough Buffy's return has been on her. Overhearing Joyce's words, Buffy decides to pack again.
At the library, Giles is horrified by what he finally uncovers about the mask. He tries to phone Buffy, but party-goers fail to relay the message. Giles decides to drive to the party when he hits a man in the road. Giles gets out of the car and finds the man reanimated. Giles barely escapes oncoming zombies as bodies rise all over Sunnydale.
Willow finds Buffy in the bedroom and expresses her disapproval. Joyce joins her and when Buffy tries to leave the party, she stops the merriment. Xander chimes in on the gang-up as well, telling her that running away like she did was selfish and stupid, and just when Buffy is about to break down completely, zombies crash in through windows and doors. Several guests are killed. Oz and Cordelia hide in a downstairs closet while Buffy and others rush upstairs with a gravely injured Pat. In the bedroom, Willow checks Pat's pulse and finds she is dead.
Giles arrives to tell Oz and Cordelia about the mask containing the powers of a Nigerian zombie demon, Ovu Moboni. Whichever zombie puts it on becomes the demon -- and Pat does. Other zombies are cowered while Buffy soon realizes that its gaze hynotizes the recipient when its eyes flash in the direction of the recipient. Buffy pushes Pat out of the window when it is about to kill Willow. Oz tries to tell Buffy about how to kill it when he is hypnotized. Buffy takes the opening to plunge a shovel into its eyes. It vanishes along with all the other zombies. The gang reconciles.
The next day, Giles tries to convince Snyder to let Buffy return. When he refuses, Giles applies a little physical pressure. In the coffee shop, Willow tells Buffy about her dabbling in magic and the two are again best friends.