After Anya grants a grusome vengeance wish, she starts to have second thoughts.  When Willow lets Buffy know about it, Buffy sets out to kill Anya.  Xander doesn't like it and tries to save her.  In the meantime, Willow contacts D'Hoffryn who shows up at the Buffy vs Anya fight.  Anya tells D'Hoffryn that she wants the spell reversed even though it will cost the life of a vengeance demon.  Prepared for death, Anya gets her wish, but not like she thought.