Chosen

In which Willow supports girl-power, Anya falls, Spike gives his all, Sunnydale is a pit, and Buffy doesn't say a word.

Official back-of-box synopsis:

After being struck by an ingenious idea, Buffy and the potential slayers launch an all-out war on the First and the army of uber-vamps massing beneath the highschool.

Cross-reference:

episodes in which major characters die:

• Prophecy Girl
  Buffy drowns, if not permanently
• Becoming (part 2)
  Buffy sends Angel to hell to save the world
• The Wish
  Another reality in which Xander, Willow, Cordelia and Buffy all die
• The Body
  Joyce
• The Gift
  Buffy saves the world a lot, rather than let Dawn die
• Seeing Red
  Tara
• this episode
  Anya. Spike.

episodes where the Mutant Enemy guy is different:

• Becoming (part 2)
  he "needs a hug"
• Amends
  wears a Christmas hat
• Graduation Day (part 2)
  he wears a mortar-board hat
• Once More, With Feeling
  he sings "grr-arrgh" (it's Joss' voice)
• Storyteller
  The "we are as gods" one.
• this episode
  He turns to the camera for a moment

Cast:

• Sarah Michelle Gellar as Buffy / The First
• Alyson Hannigan as Willow
• Nicholas Brendon as Xander
  

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• Anthony Stewart Head as Giles
• David Boreanaz as Angel
• James Marsters as Spike
• Eliza Dushku as Faith
• Emma Caulfield as Anya
• Michelle Trachtenberg as Dawn
• Tom Lenk as Andrew
• DB Woodside as Principal Wood
• Indigo as Rona
• Iyari Limon as Kennedy
• Sarah Hagan as Amanda
• Nathan Fillion as Caleb / The First
• Felicia Day as Vi
• Mary Wilcher as Shannon
• Lisa Casaba as Injured Girl
• Katie Gray as Indian Girl
• Ally Matsumura as Japanese Girl
• Kelli Wheeler as School Girl
• Jenna Edwards as Trailer Girl
• Julia Ling as Potential With Power
• Demeter Raven as Girl At Bat