Wrecked

In which Willow visits a crack, err, magic house, drives while under the influence, and hits rock bottom and a wall.

Official back-of-box synopsis:

Amy introduces Willow to a warlock whose powerful black magic proves addictive; Buffy and Spike deal with the aftermath of their night of passion.

Cross-reference:

episodes featuring dairy products:

• Never Kill A Boy On The First Date
  String Cheese is served in the cafeteria.
• Enemies
  The mayor pours Faith a glass of milk. She doesn't drink it.
• Living Conditions
  Kathy and Buffy argue over milk. Sid The Wiley Dairy Gnome is accused.
• Superstar
  Anya needs help opening a milk carton. Xander's not man enough.
• Restless
  The Cheese Man wears the cheese, it does not wear him.
• Once More, With Feeling
  Anya's accused of eating skeezy cheeses
• Storyteller
  The Cheese Man makes a brief flashback appearance.
• this episode
  Willow mentions keeping "stinky yak cheese in my bra"

Cast:

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

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• Elizabeth Anne Allen as Amy
• James Marsters as Spike
• Emma Caulfield as Anya
• Amber Benson as Tara
• Jeff Kober as Rack
• Michelle Trachtenberg as Dawn
• Fleming Brooks as Mandraz
• Mageina Tovah as Jonesing Girl
• Michael Giordani as Jonesing Man
• Colin Malone as Creepy Man
• Mark Oxman as Espresso Pump Worker