Sunnydale High is boasting a new cultural exchange program --students from other countries being hosted by local families, and a celebration of culture's dance is being plan. Everything is swell until Xander finds out that Buffy's student is a guy. At a school museum trip, a 500-year-old mummy, holding a cursed seal which serves as a warning to any who wake her, is on exhibit. When everyone leaves, dimwitted student Rodney tries to take the seal. It breaks, and the mummy arises, grabs him, kisses him and mummifies him. When Rodney turns up missing, Buffy, Giles, Xander and Willow go to the museum to look for clues and find him mummified, and a man with a knife jumps out at them. Giles tries to decipher what's left of the seal, but they are ancient pictograms.

Buffy's exchange student arrives at the bus station, only to meet the same fate as Rodney. From this latest kiss, the 500-year-old mummy transforms into Empada, a beautiful Peruvian teenage girl who pretends to be the exchange student. Xander goes gaga over her and Giles asks her to help him decipher the seal. She says the picture of a man with a knife represents a bodyguard. As Xander hangs out with Empada, the knife guy shows up again, looking for the rest of the seal. Empada, shaken, tells Giles to destroy it, but Giles wants to go back to the museum to find the missing parts. Knife guy returns in the ladies' room, and Empada finally kisses and mummifies him, too. Xander takes Empada to the school dance, and Buffy discovers the real exchange student's mummified corpse in her trunk. She and Giles realize Empada's the mummy. It seems she was in a similar situation to Buffy's -- she was chosen to defend her people, and was killed at 16. Meanwhile, things are getting hot and heavy at the dance with Xander and Empada, but she is starting to turn back into a mummy. She must kiss someone quickly or it will be too late. She runs away from Xander and goes to the museum to try to break the seal that Giles is about to restore. Buffy saves Giles before Empada kisses him, but gets thrown into the tomb. When Willow tries to help, Xander intervenes and offers his own life instead. Buffy escapes from the tomb just in time to pull the now-mummified Empada off of Xander, and the poor guy's dance partner breaks into pieces.