Sunnydale High has been destroyed, the world saved (again) and now Buffy and her friends have to face a brand new challenge: college. As Buffy tries to juggle slaying and studying, a mysterious team of crack demon-hunting soldiers arrives in Sunnydale, and an old enemy returns.
American high school dramas seem to inevitably reach that point where it's no longer possible to keep the kids in school any more and send them off to college, which can also be a shark-jumping moment as the old, successful paradigm is dropped and the show struggles to adapt to a new one. In the case of Buffy's fourth season, the show adapts to the new order with surprising grace. It helps that there's also a turnover of cast to keep things fresh. Angel and Cordelia left for their own spin-off show at the end of Season 3 and it's not long before Oz is also out of the picture. Cue new regular characters Riley Finn and Tara, with returning villains Spike and Anya promoted to regulars as well.
This freshness also extends to a more realistic take on the "moving on from high school" trope. Only Buffy and Willow make it to college, with Xander entering the world of full-time employment and Giles taking the year off, effectively.
This change and growth is a good thing, which the show mostly handles well in terms of characterisation. Unfortunately, it leads to a somewhat underwhelming main story arc. After the battles against the Master, Angelus and the Mayor, Season 4's main villain takes an inordinate amount of time to emerge. We're well past the halfway point of the season when the main threat becomes clear and even then it feels kind of underwhelming. The stand-alone episodes also struggle to pick up the slack, with several of the show's worst episodes since Season 1 (such as the remarkably poorly-conceived Beer Bad) falling in Season 4.
Still, this is Buffy and the show refuses to let itself get dragged down by a couple of weak spots. The dialogue sparkles even in weaker episodes, the actors are all comfortable in their roles and the increased production value results in better effects (although less said about Adam's prosthetics the better). The new additions to the cast are mostly solid (although Riley is a very bland character) and the season gives the cast chances to show off their other talents, such as Giles's guitar playing and singing. But the season's triumph is in giving us two bold, unusual and experimental episodes which rank among the show's finest.
Hush may be the show's finest hour, or at least the finest hour you can show people without a lot of other context (unlike The Body, Once More With Feeling and Conversations with Dead People). A bunch of demons show up in Sunnydale and steal everyone's voices, leaving the cast having to fight an enemy without the ability to speak. Given how much TV writing is conveyed by dialogue, making a speech-less episode work is a monumental challenge but one the cast pulls off brilliantly.
The other such episode is Restless, the season finale which takes place in a shared dream experience. "Dream episodes" are ten-a-penny in SF and fantasy franchises, but few capture the lucid surrealness of a dreaming experience as well as this one. It's a busy episode with some very clever writing which addresses everything which has happened in the season and also starts setting up Season 5 (which opens with one of the biggest whiplash moments of surprise of any TV show).
Season 4 (****, but ***** for Hush and Restless) is not the best season of Buffy and may in fact have the weakest overall story arc. But that is saved by the strong dialogue, characterisation and performances, and two of the best episodes the series ever produced. The season is available now as part of the complete Buffy the Vampire Slayer DVD box set (UK, USA).