He reluctantly helps the Scooby Gang throughout the season and even begins to fight on their side after joyfully learning that he can harm fellow demons.
The Initiative's more sinister secret purpose is revealed when its composite demonic cyborg, Adam, kills Walsh, then escapes and rampages through the town.
Series creator Joss Whedon served as executive producer and showrunner, and wrote and directed four episodes including the season premiere and finale.
Beginning with this season, Buffy the Vampire Slayer and its spin-off Angel both aired on The WB Television Network.
Angel (David Boreanaz), Cordelia Chase (Charisma Carpenter) and Wesley Wyndam-Pryce (Alexis Denisof), who had been introduced in Buffy, became main characters in the spinoff series.
After learning that he was in town, Buffy (Sarah Michelle Gellar) visits L.A. in the Angel episode "I Will Remember You" to express her displeasure in his not telling her that he was there.
Sarah Michelle Gellar was nominated for a Golden Globe Award for Best Actress – Television Series Drama.
The season was nominated for two Television Critics Association Awards, for Outstanding Achievement in Drama and Program of the Year.
Robert Bianco from USA Today comments, "(i)n a medium in which producers tend to grow bored with their own creations, either trashing them or taking them in increasingly bizarre directions, Whedon continues to find new ways to make his fabulously entertaining series richer and more compelling.
"[26] Alan Sepinwall in The Star-Ledger calls it a "magnificently daring episode", explaining "(w)hat makes it particularly brave is that, even when Buffy has been failing to click dramatically this year, the show has still been able to get by on the witty dialogue, which is all but absent after the first few scenes.
Whedon finds ways to get around that, with several cast members—particularly Anthony Head as the scholarly Giles and Alyson Hannigan as nervous witch Willow—proving to be wonderfully expressive silent comedians.
"[27] In the New York Daily News, David Bianculli states that the episode is "a true tour de force, and another inventive triumph for this vastly underrated series.
"[28] Robert Hanks from The Independent in the UK writes that "Buffy the Vampire Slayer, in most weeks the funniest and cleverest programme on TV, reached new heights" with "Hush".
Club calls it an "episode unlike any other, with a lusher score and some of the most genuinely disturbing imagery I’ve yet seen on Buffy.
"[30] The episode was included among 13 of the scariest films or television shows by Salon.com, and justified by Stephanie Zacharek, who states it "scans just like one of those listless dreams in which you try to scream, and can't.
Featurettes include, "Spike Me", which details the character of Spike; "Oz Revelations: A Full Moon", which details the departure of the character with insights by actor Seth Green; "Hush", where cast and crew members discuss the unique episode; "Buffy: Inside Sets of Sunnydale" showcases all the sets on the show with tours of sets; "Buffy: Inside the Music", which details the music and bands featured on the show; and "Season 4 Overview", a 30-minute featurette where cast and crew members discuss the season.