This is, technically, the season ender.  The end of the season long story arc of the Initiative which, surprise surprise, turned out to be the focus of the season as the Mayor was for season three and Angel was for season two.  There's one more show but it is desert.

Show opens as Buffy checks out Sunnydale High School, likely looking for Riley but he's not there.  As we all know he's at Adam's lair, chatting.

Adam lets Riley know that Riley has a chip, in his chest that is into his nervous system, that allows Adam (and presumably allowed Dr. Walsh) to control him like a puppet.  Adam demonstrates this by commanding him to sit down, be silent, cluck like a chicken.  (Okay, I made that last one up.)

Spike arrives to gloat and brag to Adam and Adam takes that opportunity to check that Spike has given Buffy the clues to get her into the Initiative complex.

Spike: "Right. The Initiative. But getting her there, that's what the bleedin' disks are for, idn't it? Well, the little witch gives her the info and pop, Alice heads back down the rabbit hole."
Adam: "The witch?"
Spike: "Uh, Willow. About so high. Perky. Good with math. Natural choice."
Adam: "Her friend?"
Spike: "Right."
Adam: "One of the friends from whom you so efficiently separated her."
Spike: "Damn right I did. You should've seen 'em. They won't be talking to each other for a long, long-- Hang on.  I think I might have detected a small flaw."
Adam: "So you failed."
Spike: "W-- Hey, you're supposed to be so smart, you let me plan this thing. Okay, let's not quibble about who failed who. The important thing is making sure the Slayer is where we want--"
Adam: "Go."
Spike: "Gone. So, uh, we'll do this chip thing when I get back."

We then have a couple of short scenes of people feeling sorry for themselves.  Anya trying to console Xander.  A hungover Giles trying to be cool with Willow and Tara.  A despondent Buffy puppy dog eyeing an old picture of the Scoobies until, with steel in her eyes she grabs a big axe and goes to Adam's cave where Forest was killed.  There she runs into Spike who reminds her that she should get on Willow about the discs and not let some little tiff keep her from her sacred birthright.  A light bulb goes off in Buffy frontal lobe and she agrees.  She gathers the Scooby Gang and asks them to meet her at the university.  They all show up, standing on different paths at an intersection.  (Nice symbolism.  Handy there being four.)

Buffy: "Where's Anya?"
Xander: "Oddly, Anya decided not to join us despite all the fun we had at our last meeting."
Willow: "And I don't think Tara felt welcomed."
Buffy: "Why? Because of the things we said? Will, who told you that we were talking behind your back,
specifically?"
Willow: "Well, I-- Spike, specifically. But--"
Buffy: "And who told you that we thought you'd be better off joining the Army?"
Xander: "That's not... exactly what he said."
Giles: "Um, uh, Spike can be very convincing when-when-when, uh... I'm very stupid."

The gang puts two and two together and figure that Spike was working for someone...

Xander: "Spike's working for Adam!? After all we've done-- Nah. I can't even act surprised."

And that Adam is too big for Buffy to handle on her own.  They retire to Giles to plot.

Meanwhile, Adam has taken Riley to a secret lab.  There we find that Adam has reanimated Maggie and Dr. Angleman as Bionic Zombies and we hear the true plan.  Demons have been getting themselves thrown into the containment area so that they can attack from within.  There will be a huge battle between the demons and the initiative soldiers with Buffy thrown in to raise the chaos level.  And then the Zombie Doctors will take all the bits and make an army of Adams.  Forest (enter Forest) and Riley will be the first.

At Giles' the gang runs into a solution and a problem.  There is a spell that would paralyze Adam long enough for Buffy to remove his power supply.  But it requires an experienced witch (like Willow) to recite a spell in Sumerain (which Giles speaks).  Xander throws of an offhanded comment about finding a way to merge Willow's Wiccy in with Giles' languages and thus, an idea is born.

The Scoobies break into the Initiative and conveniently rehash their plan so we're let in on it.  They're going to use a spell to give their separate skills to Buffy.  Giles warns them that it might be dangerous but this seems to be their only choice.  Once again they break into the Initiative...

Willow: "Nervous?"
Xander: "No way. I'm full of that good old Kamikaze spirit."
Giles: "Xander, just because this is never going to work there's no need to be negative."

Rappeling down the elevator shaft Willow and Buffy have a heart to heart.  Both agree that they haven't been the best of friends and each tries to take the blame before admitting that fault was equal.  The last few feet are a free fall clinch that lasts until Xander arrives to join in on the reconciliation...

Buffy: "Xander!"
Willow: "Oh, wonderful Xander!"
Buffy: "You know we love you, right?"
Willow: "We totally do!"
Xander: "Oh, God, we're gonna die, aren't we?"

Pretty much the first thing to happen is that the Scoobies are captured.  However, once the demons escape they manage to overcome their few guards.  They then make a beeline for Room 314 (using teamwork and back watching to protect each other) where the three prepare the spell and Buffy heads off to the secret lab.  There she finds an immobile and silent Riley, a homicidal Forest and a smug Adam.  Adam orders Forest to kill Buffy and heads to a control room where he can monitor the carnage.  Buffy and Forest fight with Buffy just barely holding her own while Riley watches helplessly.  Slowly Riley regains enough control to break a flask and, using the jagged glass and a really gross sound effect, rips the chip from his chest just as Forest is about to dispose of Buffy...

Forest: (after backhanding Buffy) "That all you got?"
Riley: "No.  She has me."

Riley tells Buffy to amscray to get Adam, he'll finish up here and catch up.  Buffy takes off after Adam who tries to kill her with a new modification of his; a minigun in his left arm.  Buffy dives behind a console just as the Scoobies complete their spell.

I'm not sure why but whenever they want to signify major power they make the poor actors wear coloured contacts.  They made Sally Kellerman and Gary Lockwoord wear them in the original Star Trek and they use the same effect here.

Anyway, Buffy pops up with golden eyes and a fan directed at her hair.  Using the power of the four of them she shields herself from the bullets, turns a mini-LAW into a dove and finally slams Adam into a wall and rips out his power supply.  Riley arrives in time to see Adam fall down, Buffy dispose of the power supply and then catch the collapsing Buffy as the spell ends.

In Room 314 the three Scoobies are left weakened so that, of course, a demon breaks in.  Fortunately, Spike arrives to save them.

Spike: "Nasty sort of fellow. Lucky for you blighters I was here, 'ey?"
Giles: "Yes. Uh, thank you. Although your heroism is slightly muted by the fact that you were helping Adam to start a war that would kill us all."
Xander: "He probably just saved us so we wouldn't stake you right here."
Spike: "Well, yeah. Did it work? Well, then everything's all right. We all get to be not staked-through-the-heart. Good work, team."

Buffy and Riley arrive and the whole group have a feel good moment...

Willow: "Wasn't it amazing"?
Xander: "You were great."
Buffy: "We were great."
Riley: "We still got men out there."
Spike: "Well, let's go save 'em, by gum!"

...before running off to save the rest of Riley's men from the demon hordes and escape.

The show ends with a bunch of X-file extras watching videos of the final battle.  As the head shadowy man says, "It was an experiment. The Initiative represented the government's interest in not only controlling the otherworldly menace but in harnessing its power for our own military purposes. The considered opinion of this counsel is that the experiment has failed. Once the prototype took control of the complex, our soldiers suffered a forty percent casualty rate. And it seems that it was only through the actions of a deserter and a group of civilian insurrectionists that our losses were not total. I trust the irony of that is not lost on any of us? Maggie Walsh's vision was brilliant but, ultimately, insupportable. The demons cannot be harnessed. Cannot be controlled. It is therefore our recommendation that this project be terminated and all records concerning it expunged. Our soldiers will be debriefed. Standard confidentiality clause. We will monitor the civilians. And the usual measures prepared should they try to go public. I don't think they will. The Initiative itself will be filled in with concrete. Burn it down, gentlemen. Burn it down... and salt the earth."

Random thoughts

1. Since when has Giles worn an earring?  Did I miss it or did Anthony Head forget to take it off.
2. I would like to personally thank Joss for reading my last summary's random thoughts, jumping into a time machine and filming the scene in answer to my request.  Not exactly as I pictured it but considering the Scoobies were busy it works.  And the symmetry of having a boyfriend ask it in season 2 and a boyfriend answering it in season 4 is not lost on me.
3. Apparently (I missed it) Spike could have made like a bunny and escaped.  However, I'm a bit dubious that he remained for altruistic reasons.  More likely he was just happy to be able to hurt things.