Janine is giving another woman a tour of the firehouse and letting her know never to touch anything in the basement or ask Peter for assistance. Meanwhile, Egon and Winston are trying to build a portal to the Netherworld. However, when they leave, Slimer flips the switch, allowing six glowing blobs to emerge, which turn into little creatures.
In the kitchen, Janine wants to take Egon for dinner with her family, but he isn't sure. Janine then arrives, introduces the second woman as Louise, and reveals that she's a temp secretary. Peter crushes on Louise, then the creatures from the machine walk in and one of them uses a little weapon to zap Peter and Slimer.
While Egon meets the Melnitzes and is sprayed in the face by a boy with a water gun, Ray notices one of the creatures and identifies it as an imp. Winston works on a particle thrower, and Ray tells everyone about the imps, who continue to run rampant and annoy everyone. Meanwhile, Egon is saving some dinner in hopes it will grow mould for his collection.
Ray retrieves a trap, and Peter tries to zap an imp, but it causes it to multiply into six. He tries turning up the power, but this just makes all the imps multiply. Winston calls Egon over, and Janine decides to tag along, and then Ray goes to pick them up. Peter "reverses the polarity" on his proton pack, but when Egon and Ray enter, they warn him not to. However, they are too late and the imps merge together and turn into a giant demon.
The demon bursts out the walls and begins rampaging through New York. The power goes out, and Louise and Slimer hide in the basement workroom. Louise flips the switch of the portal, mistaking it for a generator, and then three ghosts emerge. While the guys try to zap the demon, only to find it's immune to proton streams, one of the ghosts puts on a proton pack and chases the ladies and Slimer with it. The Ghostbusters try to ram the demon, but that doesn't work either.
The demon starts chasing the Ecto-1, with the fuel tank running low, but Egon surmises that if they up the power, they'd be able to catch it. Meanwhile, the ghosts are still terrorising the women and Slimer. Egon and Ray go off to make a proton pack more powerful, while Winston and Peter keep the demon busy. Then, Janine finds Peter's "polarity-reversed" proton pack and fires at the ghosts, who surrender.
Just as Peter and Winston are getting tired, Egon and Ray trap the demon. Then, the guys return to the firehouse to find it a complete mess. Louise resigns, Janine decides to take the next day off as well, and then she throws the guys cleaning supplies so they can clean up the mess.
This episode provides examples of
- Amusing Injuries: The imps give Peter and Slimer painful, but relatively harmless, electric shocks.
- Blowing a Raspberry: One of the imps blows a raspberry.
- Bratty Half-Pint: The little boy who's some relative of Janine's (possibly nephew, brother, or cousin) sprays Egon with a water balloon and chases a cat.
- Damsel in Distress: Janine and Louise are being threatened by ghosts, but manage to scare them off themselves with a proton pack.
- A Day in the Limelight: Downplayed — most of the focus is on the Ghostbusters, but Janine gets more screen time than usual.
- Did You Just Flip Off Cthulhu?: Peter insults the demon to its face twice, the first time when about to zap it, and the second time to distract it.
- Dramatic Irony: We see the imps before Peter, so he initially thinks it was the coffee pot that zapped him.
- Evil Laugh: All of the baddies in this episode occasionally chuckle maniacally.
- From Bad to Worse: The imps were merely annoying, but then they become a demon who's an actual threat, not just to the Ghostbusters, but to NYC as a whole.
- Fusion Dance: The demon is a result of the imps merging together.
- The Hyena: The imps, demon, and ghosts sometimes burst into evil laughter.
- Last-Second Joke Problem: The ghosts have surrendered, and the Ghostbusters have trapped the demon, but now, they have a big mess to clean up.
- Layman's Terms: Ray's first explanation of the imps is full of Sesquipedalian Loquaciousness, so he has to explain again in normal terminology.
- No-Sell:
- The imps can't be killed or confined with the proton beams; they just multiply.
- Subverted for the demon, who initially seems like it can't be trapped, but it can; it just needed more power.
- Not So Stoic: Egon acts uncharacteristically nervy about meeting Janine's family.
- Red Is Violent:
- Downplayed for the imps, most of whom are red, and who zap people with small weapons, but they're mostly harmless.
- Played straight for the demon, who charges through the city and attacks people.
- Screaming Woman: Louise screams when the demon forms.
- Slapstick: Ray trips over Winston.
- Speak in Unison: When Peter says he reversed the polarity, Egon and Ray echo back, "Reversed the polarity?!" in unison.
- Split Screen: When the Ghostbusters are responding to the demon at one point, the screen splits four ways.
- Theme Music Power-Up: The theme tune plays as Janine threatens the ghosts.
- Unwitting Instigator of Doom:
- Both Slimer and Louise flip the switch to the machine, not knowing it will release first imps, then ghosts.
- Peter "reverses the polarity" on his proton pack, unaware that it'd cause the imps to turn into a demon.
- Water Guns and Balloons: One boy sprays Egon with a water gun twice.
