Hush

In which Buffy has no voice, but she must scream. Though what with the hearts being cut out, the guys in straight-jackets and the most frightening, and polite, villains that ever floated by, you'd think that the screams of the audience would be sufficient.

Official back-of-box synopsis:

Silent night - a silence falls over Sunnydale when the otherworldly beings come to town and steal the power of speech from all the residents

From the old WB Buffy website:

SILENT NIGHT - A silence falls over Sunnydale when otherwordly beings come to town and steal the power of speech from all the residents. Meanwhile, Riley gets his first clue to Buffy's slayerside when they have a fight with the outside visitor, and Willow attends a wicca group that's not all she had hoped.

Links:

This episode's page at http://www.restlessbtvs.com/, the Restless BTVS Trivia Guide

This episode's page at http://www.vrya.net/bdb/, the Buffyverse Dialog Database

Cross-reference:

episodes featuring dream sequences:

• Welcome To The Hellmouth
  Buffy's dreaming the very first time we see her
• Teacher's Pet
  Xander fantasises about being a rock god with Buffy at his feet
• When She Was Bad
  Buffy dreams that Giles attacks her
• Innocence
  Buffy's dream tells her Jenny's keeping secrets
• The Prom
  Buffy and Angel in a nightmare wedding
• Graduation Day (part 2)
  Faith gives Buffy hints on how to defeat the mayor, plus something about 7-3-0...
• Restless
  The First Slayer invades the dreams of Willow, Xander, Giles and Buffy in turn
• The Weight Of The World
  Buffy's locked in a recurring dream from which Willow has to rescue her
• this episode
  A spooky little girl with the answer to the mystery of the Gentlemen

episodes in which Buffy tries to have a normal boyfriend:

• Never Kill A Boy On The First Date
  Owen
• Faith, Hope And Trick
  Scott
• Living Conditions
  Parker
• this episode
  Riley

episodes with major moments in Willow and Tara's relationship:

• Who Are You?
  "I am, you know" - Willow and Tara get together for the first time
• The Yoko Factor
  Willow says for the first time that Tara's her girlfriend - "bloody hell!"
• The Body
  their first public kiss
• Once More, With Feeling
  Tara realises Willow's using magic to influence her
• Seeing Red
  losing Tara, Willow will never be the same again
• this episode
  Willow and Tara meet

Cast:

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

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• Anthony Stewart Head as Giles
• James Marsters as Spike
• Emma Caulfield as Anya
• Marc Blucas as Riley
• Lindsay Crouse as Professor Walsh
• Phina Oruche as Olivia
• Leonard Roberts as Forrest
• Amber Benson as Tara
• Brooke Bloom as Wanna-blessed-be #1
• Jessica Townsend as Wanna-blessed-be #2
• Camden Toy as Gentleman #1
• Charlie Brumbly as Gentleman #2
• Doug Jones as Gentleman #3
• Don W Lewis as Gentleman #4
• Carlos Amezcua as Newscaster
• Elizabeth Truax as Little Girl
• Wayne Sable as Freshman