A class of children is visiting the firehouse with their teacher. Peter and Slimer are the only ones around to greet them, since the rest of the guys are giving a lecture and Janine is having a day off. Two boys look at Peter's desk, and notice a snow globe, which he reveals was a souvenir from a dangerous case. He then starts telling the story, which begins with a man named Jeffers Martin visiting the firehouse.
He offers them an opportunity to purify a house called Heck House, but Egon and Ray instantly try to bail. They reveal that for fifty years, everyone who went there either died or was traumatised. Jeffers then reveals that a wealthy man named E. Henry Merriweather, who was interested in the supernatural, left money to the Ghostbusters if they could stay the whole night in the house without any proton packs, and promises all of them, plus Slimer, a million dollars each if they can.
Everyone is keen on that money, except for Egon, who still refuses to do it. However, that night, he accompanies them anyway. When Jeffers leaves, the Ghostbusters and Slimer have to deal with a falling chandelier in the foyer, a haunted light switch and a monster under the bed in Ray's bedroom, and all of the furniture being upside down in Winston's room. Egon, meanwhile, is in the library, which is relatively safer (only one book moves, and stops when he tells it not to).
Slimer is then sucked into a hidden passage, where he meets dancing skeletons. When he escapes them, he finds a demonic horseman, a giant, black cat, and a pack of ghostly dogs. He meets up with a nonchalant Peter, then they all unite to eat sandwiches. Egon reveals that there are 2,436 ghosts in Heck House, which is odd since not only did the second-most haunted house only have 25, there were only twelve people living in Heck House.
They then try to escape, only to find the exits bricked up. Peter tries to escape with a pickaxe, but the wall repairs itself. Egon goes back to the library to do research, then the lights go out, and Ray and Winston disappear. Peter goes off to look for them, while the chair Slimer is on comes to life and holds him down. Winston finds some knights who invite him to join them, while Ray finds some possessed sheets in the laundry. He tricks them into jumping into the dryer, then is wrapped up like a mummy by a towel dispenser. Peter and Winston trick the knights and horses into jumping into a painting, then they find Ray, but also a dragon-like ghost.
Slimer breaks free of the chair, then in the library, Egon revealed that the previous owner, Joshua Heck, deliberately created the world's most haunted house by enchanting 2,346 books of ghost stories to come to life. They rewire the house to convert it into a giant ghost trap, escape, and then as the ghosts are trapped, the house itself shrinks. However, they don't get their money as they came out five minutes too early. This angers Peter, but he decides to keep Heck House as a souvenir, and in the present, he reveals that he put it in the snow globe to use as a paperweight. Then, the shadow of the dragon ghost appears in the shrunken house, scaring the boys.
This episode provides examples of
- Alliterative Title: The Haunting of Heck House.
- Animate Inanimate Object: A chair comes to life and holds Slimer in place.
- Arbitrary Skepticism:
- Despite ghosts and dragons being shown to exist, Peter doubts the existence of a ghost dragon.
- Peter also laughs at Winston's claim of a many-eyed ghost despite all he's seen.
- Bedsheet Ghost: Played for Horror —- ghosts possess actual bedsheets.
- Bittersweet Ending: The evil ghosts are contained, and the Ghostbusters and Slimer survived unscathed, but they finished five minutes too early and so don't get their million dollars each.
- Bound and Gagged: Ray gets tied up in a towel dispenser.
- Cheerful Child: The kids at the beginning are happy and energetic.
- Coincidental Accidental Disguise: Ray accidentally ends up looking like a ghost by being wrapped up in a towel dispenser.
- Conforming OOC Moment: When the house collapses, the Ghostbusters and Slimer all punch the air, even Egon.
- Continuity Nod: Peter mentions that they made a movie out of the events of their first case, which was first revealed in "Take Two".
- Creepy Changing Painting: Slimer is shocked by a person in a painting turning into a ghost.
- Dark Is Evil: The evil, giant, ghost cat is black.
- Dem Bones: A group of dancing skeletons is seen once.
- Eat the Camera: When Slimer flies off screaming, we see inside his mouth.
- Extra Eyes: Discussed when Winston says he saw a many-eyed ghost.
- Foregone Conclusion: While it's never revealed until the end whether the Ghostbusters and Slimer will win their money, it's a given that they survive, since in the present, Peter and Slimer can be seen, and Peter mentions "the guys" are giving a lecture and he seems too happy for Ray, Egon, or Winston to have died.
- Foreshadowing: When Winston sees a many-eyed ghost, Peter says, "You read too many books". This foreshadows that the ghosts are book characters come to life.
- Forgot About His Powers: At one point, Slimer leaves an Impact Silhouette, despite the fact that he can fly through things without breaking them.
- Ghostly Animals: Among the ghosts are a (giant) cat, some dogs, and some horses.
- Gilligan Cut: Egon refuses to go to Heck House, but the next scene shows him along with the others at Heck House.
- Glowing Eyes of Doom: One ghost's eyes glow.
- Haunted House: Exaggerated — Heck House is haunted by 2,346 ghosts.
- Horrible Camping Trip: Peter claims he learnt there was nothing too big to handle during a camping trip with his father.
- I Don't Like the Sound of That Place: Downplayed — the dangerous house is called Heck House.
- Impact Silhouette: Slimer leaves a ghost-shaped hole in the wall once when he tries to escape.
- "Join Us" Drone: One of the knight ghosts tells Winston to join them.
- Joke and Receive: Subverted — Peter jokes about books flying off the walls, then one looks like it's going to... but then Egon berates it, so it doesn't.
- Lightmare Fuel: While Heck House is mainly portrayed as a very scary and dangerous place, there are also funnier things like the upside down bedroom and the singing skeletons.
- Oh, Crap!: Ray looks scared when he discovers the exits are bricked up.
- Mega Neko: One of the monsters in the house is a giant cat.
- Midnight Snack: The Ghostbusters and Slimer eat sandwiches at one point, and the episode takes place at night.
- Mistaken for Undead: When Ray is wrapped up like a mummy, Peter thinks he's one of the ghosts.
- Mythology Gag: Two references to the original movie are made:
- First is when Peter teases Egon about how their first case involved a haunted library.
- Second is when Egon mentions Gozer being one of the entities they dealt with.
- Names to Run Away from Really Fast: Downplayed for the summoner of the ghosts, Joshua Heck, whose last name is a euphemism for "hell" but generally isn't used to literally refer to the place, since "hell" is often only considered profanity if you're not literally referring to the place.
- Nightmare Fetishist: Joshua Heck deliberately sought out to live in the world's most haunted house.
- Ninja Pirate Zombie Robot: One baddie is a dragon ghost.
- Not So Stoic: Egon is a bit more openly nervous than usual during this episode, then later punches the air after the house shrinks.
- Playing with Fire: The dragon ghost can make fire.
- Psycho Pink: Downplayed — one ghost has pink eyes.
- Quaking with Fear: Slimer shakes after encountering the skeletons, horsemen, and ghostly animals.
- Red Eyes, Take Warning: One ghost has red eyes.
- Sealed Evil in a Can: The ghosts are now trapped in the shrunken house.
- Seen It All: Being a Ghostbuster, Peter initially isn't swayed at the thought of a haunted house.
- Shout-Out:
- The title parodies ''The Haunting of Hill House.
- A house that kills people in one night is a reference to The Ghost Breakers.
- Egon mentions "The Whateley House", referencing The Dunwich Horror.
- Peter's line about being out of bubble gum references a line from They Live!.
- At one point Peter calls Slimer "Lassie".
- Status Quo Is God: The Ghostbusters and Slimer never end up winning their million dollars each.
- Stealthy Teleportation: One ghost appears with no sound or flash.
- Swallowed Whole: One skeleton swallows Slimer.
- Things That Go "Bump" in the Night: One ghost is under Ray's bed.
- This Is Gonna Suck: Egon at one point stoically states that converting the house to a ghost trap may kill them.
- Unicorn: One of the ghostly horses has a horn.
- Whole Episode Flashback: Most of the episode takes place in the recent past.
- Wild Take: Downplayed when Slimer looks a little buggy-eyed during one scare he gets.
- You Watch Too Much X: When Winston says he saw a many-eyed ghost, Peter says, "You read too many books".
