It's Halloween, and Slimer is accompanying some kids trick-or-treating. As they leave a woman's house, they run into some little gnome-like creatures, but mistake them for other kids. The kids leave to trick-or-treat some more, but Slimer is suspicious and follows the creatures. He snatches the candy and shows the kids, then explains that the "kids" were actually goblins. One of the boys, Jason, doesn't believe him, but the other boy, Donald, and the girl do, and they decide to check them out.
They all follow the goblins into Ghostbusters HQ, where the Ghostbusters and Janine pull a Halloween prank on them. Everyone parties for a while, but then Slimer sees the goblins running into the basement through the closed door. He tells the kids, who walk after, only to find the door locked. Slimer goes through the door to find the goblins messing with the containment unit, then the alarm sounds, sending the guests running home.
The Ghostbusters knock down the basement door and find that Samhain (from "When Halloween was Forever") has escaped. Everyone runs out to the car, while Samhain wrecks the firehouse and assembles an army. He declares the firehouse his fortress, and the Ghostbusters try to defeat him with light again, then to trap him, but it doesn't work since he's made a force field.
The humans and Slimer drive off, while Winston uses a device on the roof to trap most of the ghosts. When the traps fill up, he delays the rest of them by venting smoke. The Ghostbusters drop the kids off at their clubhouse to keep them safe (despite them wanting to help), while Samhain tells off his underlings for being swayed by mortals.
The kids are bored in their clubhouse, then look out and see Samhain and his minions. Realising that if they're outside, the "fortress" must be empty, they decide to go out in a kiddie car and investigate, though Jason isn't so sure. Meanwhile, Egon has determined the source of the "fortress"'s power and determines that all they need to do to collapse it is change its shape.
The kids try to investigate, but find the firehouse is being guarded by goblins. They try to leave in their kiddie car, but the goblins chase them. Donald, however, knocks them over with a catapulted pumpkin. However, more monsters show up.
Egon, meanwhile, is unhappy due to not having the required knowledge of the fortress's configuration from the inside. Only spirits can enter, so Slimer is sent in with a camera in his mouth. He sneaks in, but accidentally breaks a statue, getting some of Samhain's minions' attention. They give chase, but luckily, Slimer escapes, and flies to a room where he finds the kids tied up and Samhain revealing his plan to use them as bait to kill the Ghostbusters. Luckily, Egon sees a stone with writing on it on the camera, and determines that it's the "keystone", which marks where the containment unit was, and which, if fired at, would collapse the fortress.
They drive back, then when Samhain confronts them, they pretend to surrender. Meanwhile, Janine tells Slimer to tease Samhain, who sics some of his lackeys after him. He sics more lackeys after the Ghostbusters, but they trap them, while Janine zaps the keystone.
Slimer and the kids make a break for it, and he slimes them so they can pass through walls. The fortress then collapses, the villains are re-trapped, and the firehouse rebuilds itself. Thus, everyone decides to resume their party.
This episode provides example of
- All Your Base Are Belong to Us: Samhain reshapes the firehouse into a twisted fortress from which he directs attacks.
- Arbitrary Skepticism: Jason doesn't believe in goblins, despite talking to a ghost.
- Ate It All: Slimer eats all the candy in the bowl when the woman holds out a bowl for the trick-or-treaters.
- Batman Gambit: Samhain ties the children up, knowing that the Ghostbusters will try to rescue them, so he can kill the Ghostbusters.
- Bedsheet Ghost: Slimer wears a bedsheet as part of his Halloween costume (which is especially odd since he's already a ghost).
- Blowing a Raspberry: Slimer blows a raspberry at Samhain to anger him.
- Bullying a Dragon: Exploited when Slimer deliberately teases Samhain to anger him as part of the plan.
- Children as Pawns: Samhain ties up three kids so that the Ghostbusters will come and rescue them, allowing him to kill them.
- Conforming OOC Moment: Egon and Janine are usually pretty no-nonsense, but they take part in a prank towards the beginning.
- Covered in Gunge: Exploited when Slimer rubs slime on the kids to allow them to phase through walls.
- Did You Actually Believe...?: Samhain's first line out is to mock the Ghostbusters this way.Samhain: You didn't actually think you could keep Samhain, the spirit of Halloween, locked up forever, did you, Ghostbusters?
Peter: Well, yeah, actually we did. - Did You Just Flip Off Cthulhu?: Peter calls Samhain "Pumpkin Breath" to his face.
- Ectoplasm: Exploited when Slimer coats the kids in ectoplasm so they'll be able to go through walls.
- Edible Ammunition: Donald catapults a pumpkin at the goblins.
- Evil Laugh:
- Samhain laughs maniacally when shaking the walls.
- One of the goblins laughs evilly when attacking the kids.
- First-Name Basis: Catherine refers to Ray by his first name.
- Halloween Episode: As the title suggests, this episode takes place on Halloween.
- I Don't Think That's Such a Good Idea: Throughout the episode, Jason acts the most wary about everything and isn't quite so sure he wants to help defeat Samhain as it's dangerous.
- I Surrender, Suckers: When Samhain tells the Ghostbusters to surrender, they play along and pretend to do so.
- Leaning on the Fourth Wall: The kids reference the theme song by saying they're "not afraid of no ghosts".
- Mythology Gag: Peter calls Slimer "spud", which is what Ray called him in the movie.
- Nobody Here but Us Statues: Slimer pretends to be one of the statues to hide from Samhain's minions.
- No-Sell: The guys immediately try to exploit Samhain's vulnerability to bright light, but a barrier around his new fortress keeps it from affecting him. It also keeps the proton blasts from hitting him.
- Not So Above It All: The usually-no-nonsense Egon and Janine join in on the Halloween prank.
- Oh, Crap!:
- Slimer says, "Uh-oh" when he sees the goblins going into the basement, then screams when he sees them messing with the containment unit.
- Ray says after discovering Samhain's force field, "I think we need to ... get the heck out of here!".
- When Catherine notices the monsters, she says, "Uh-oh; more company!".
- Slimer looks scared when he realises he's gotten the attention of the baddies.
- Samhain looks fearful when he sees that the keystone is being zapped.
- Samahain also when he recognizes Slimer as the Ghostbusters' ally.
- O.O.C. Is Serious Business: Samhain thinks of ghosts as his little ones and has a fatherly interest in them, but he is positively livid with the ones that failed to capture the Ghostbusters.
- Platonic Kissing: Janine kisses Slimer to compliment his bravery.
- The Pratfall: Jason is knocked onto his behind by the goblins.
- Properly Paranoid: Whereas others think the two goblins are just trick-or-treaters in costume, Slimer finds them suspicious. He's exactly right, as they open the Containment Unit when no one's looking.
- Pun: Upon arriving back at the firehouse-turned-fortress, Peter says, "Looks like the unwelcome mat is out".
- Red Eyes, Take Warning:
- Some of Samhain's goons have red eyes.
- Though normally black, Samhain sports these when berating his minions for failing to capture the Ghostbusters.
- Scary Shadow Fakeout: The kids initially mistake a woman's shadow for that of a monster.
- So Much for Stealth: Slimer calls attention to himself when trying to sneak through the firehouse/fortress by knocking over a statue.
- Speak in Unison:
- The kids and Slimer say, "Trick or treat?" in unison.
- After pranking the kids and Slimer, the Ghostbusters and Janine say, "Happy Halloween!" in unison.
- Tactical Withdrawal: With Samhain safe in his new fortress and ordering the mooks out after them, Ray suggests the guys beat their feet. Everyone agrees, piling into Ecto-1 and driving off.
- Tempting Fate: Played for Laughs at the end when Peter comments that he likes how quiet it is, but then everyone else decides to start partying again.
- Theme Music Power-Up: The theme tune plays in the background as Samhain is being defeated.
- This Cannot Be!: Egon over Samhain emerging from the Containment Unit.
- This Is Gonna Suck: When Samhain starts forming an army, Winston says, "We're gonna have our hands full on this one!" in an annoyed voice.
- Title Drop:
- When Catherine refers to herself and her friends as "junior Ghostbusters", Donald says, "Yeah, but where are the real Ghostbusters?".
- Later, Jason suggests that he, Donald, and Catherine "call the real Ghostbusters" instead of investigating the fortress.
- Villainous Breakdown: Samhain screams in a rage over his fortress coming apart. Then he panics over being sucked back into the Containment Unit.Samhain: No, not again! NOT AGAIN!
- Will Not Tell a Lie: According to Catherine, Ray never lies.
- You Fool!: Samhain refers to the Ghostbusters as "fools" for believing they could lock him up forever.
