The Ghostbusters are on their way home from a job in Upstate New York during a snowstorm, when Ecto-1 breaks down. They try to walk to civilisation, only to accidentally time-travel back to Victorian England. They enter a bar, where Bob Cratchit and Tiny Tim are buying their puny Christmas turkey, and then the PKE meter goes off. The Ghostbusters follow the readings into Scrooge's house, where the Ghosts of Christmas are, and trap them, make him pay, and leave, after which he declares "war" on Christmas.
The Ghostbusters go back to the present and Ray gets the Ecto-1 started again. They go back to HQ and Egon goes to put the ghosts in the containment unit, while the rest go to buy a Christmas tree, but Janine and Slimer say, "Bah!" at the idea of Christmas, and there are ads on Fifth Avenue for a book by Scrooge titled A Christmas Humbug.
Ray realises that they must have accidentally changed history, which is verified when a woman tells him and the others that Christmas ended after Scrooge "defeated" three ghosts in 1837. The Ghostbusters rush back to the firehouse to prevent Egon from locking the ghosts in the containment unit, but he already has. They tell Egon about the situation, and the four of them make a plan: Egon enters the containment unit and retrieves the Christmas ghosts, while the rest of them go back in time and impersonate the ghosts.
While Egon goes to return the Christmas ghosts, Peter impersonates the Ghost of Christmas Past, using a stereoscope to show Scrooge images which he claims are from his past. Winston then pretends to be the Ghost of Christmas Present and shows Scrooge the bad lives of the poor, while Egon finds the Ghosts of Christmas, but the other ghosts start attacking him. Ray impersonates the Ghost of Christmas Future with charades, then Egon delivers the actual ghosts back into the past. Egon, impersonating Jacob Marley, tells Scrooge to anticipate three ghosts, annoying him, then the Ghost of Christmas Present brings the Ghostbusters home. There, they note the oddity of the Christmas Carol story turning out to be true.
This episode provides examples of:
- Accidental Time Travel: The Ghostbusters end up accidentally walking into some space-time anomaly and time-travelling to the Victorian age. However, while it may have been accidental for them, the Ghosts of Christmas Past, Present, and Future are implied to have planted that anomaly to kill two birds with one stone.
- Adventures in the Bible: The main characters end up time-travelling to a famous story, albeit not a Biblical one. Specifically, they time-travel to A Christmas Carol.
- Butterfly of Doom: By busting the Three Christmas Ghosts before they could change Scrooge's outlook like in the original story, Scrooge would write a book taking credit for it. It would become so popular that by the 20th-century, Scrooge's attitude towards Christmas becomes the norm.
- The Cameo: While Egon's in the Containment Unit, several past ghosts are seen, including Samhain, the Sandman, and Ghash.
- Christmas Episode: While the episode isn't set right on Christmas, it's set on Christmas Eve and the main plot is trying to get Christmas back to normal.
- Did You Just Punch Out Cthulhu?: The Ghosts of Christmas, despite them being implied to be more of a force of nature than what's traditionally considered "ghosts" in the original story, are captured as easily as any of the other spirits the Ghostbusters deal with on the regular. However, Christmas Present's line about their having brought the Ghostbusters here leaves open the possibility that they let the gang capture them.
- Disguised in Drag: Peter when posing as the Ghost of Christmas Past. Scrooge notes "she" looks different now.
- Elective Mute: As in other depictions, the Ghost of Christmas Future doesn't speak while onscreen, but according to Past, he can talk when he chooses to.
- Fake Ultimate Hero: In his book, Scrooge boasts that he alone defeated the Christmas ghosts, with the Ghostbusters completely ignored.
- For Want Of A Nail: According to this episode, if Ebeneezer Scrooge hadn't reformed, he would have put a stop to Christmas and made everyone in the world cynical and stingy like him.
- Freudian Excuse: Peter's father was always away around Christmastime, leading to a lot of lonely holidays. It left him bitter and flippant about celebrating the day. Ray theorizes that telling himself Christmas was just another day was initially intended to numb the disappointment that he couldn't have the traditional happy, family-filled Christmas, and he grew to believe it after telling himself that for so many years.
- Freudian Excuse Is No Excuse: Peter ends up denigrating his own Freudian excuse by proxy while spelling out for Scooge what he was supposed to learn from Christmas Past: yes, Scrooge's past (and Peter's, for that matter) wasn't positive, but a person shouldn't let his past get in the way of making a better future.
- The Grinch: Scrooge declares "war" on Christmas and writes a novel titled A Christmas Humbug.
- Hand Signals: Posing as the Ghost of Christmas Future, Ray tries playing charades instead of talking outright. Scrooge tries to play along, though Peter thinks this will fail. Luckily, Egon arrives very early into this attempt.
- Ironic Echo: "Christmas is just another day" is said early on by Peter, only for Janine to say the same after the guys return from the past to find that they accidentally destroyed the holiday.Winston: Sound familiar, Peter?
Peter: I didn't sound like that. Besides, that was different. - Jerkass Realization: Scrooge didn't learn anything from Peter's stint as the Ghost of Christmas Past, prompting an angry reaction from Peter, whose perspective on Christmas isn't that much different.Peter: You were supposed to learn that just because you had a rotten past, that's no reason to blame Christmas. Lots of us had Christmases that weren't the best, but if you give up, you just end up denying yourself what you're so mad about never having had before. [realizing] I think maybe that's a lesson we could all stand to learn.
- Let Me Get This Straight...: After the commercial break, Peter does this to try to process how they went back in time and changed history in a way that caused people to no longer celebrate Christmas.
- Little "No": Ray whispers "No" after Egon says it's impossible to let the three Christmas ghosts out without letting the others free, too.
- The Power of Love: In the alternate present, Janine has absolutely no interest in saving Christmas, but she says she will help Egon get the ghosts out of the Containment Unit because she's in love with him.
- Race Against the Clock: To enter the Containment Unit, Egon uses a device that destabilizes his molecular density enough to make him ghost-like. He says he has one hour to find the Christmas ghosts and get out, or he'll be trapped forever. He makes it out with barely any time to spare.
- Real After All: This episode reveals that in the show's canon, A Christmas Carol really happened.
- Santa Ambiguity: An offscreen voice says, "Merry Christmas to all and to all a good night", but it's unknown if that was actually Santa.
- Saving Christmas: After the Ghostbusters accidentally change the past so that Christmas got destroyed in 1837, they have to work to bring it back by getting the Christmas ghosts back and impersonating them.
- The Scrooge:
- Peter Venkman grouses a bit about Christmas being overrated but helps his friends save it.
- When the future is changed, everyone in New York (apart from the Ghostbusters themselves) starts hating Christmas and exclaiming, "Humbug!" like Scrooge.
- Suddenly Shouting: In the altered present, Janine dislikes Christmas so much that she can't even bring herself to say the word and reacts with yells of disdain whenever it's said in her presence.Egon: Christmas.
Janine: BAH HUMBUG! - This Is Gonna Suck: Egon when he sees all the other ghosts have realized he's in the Containment Unit with them.
- Time Travel Episode: The plot is kicked off by the Ghostbusters accidentally going back in time and catching the ghosts from A Christmas Carol.
- Warning Mistaken for Threat: The Ghostbusters stumble through a temporal anomaly after getting lost and interrupt the Ghosts of Christmas Past, Present, and Future as they prepare to put Scrooge through the events of A Christmas Carol. As the Ghostbusters catch them, Christmas Present calls out that if they don't let them go, Christmas will suffer. Given that they've long since been inured to threats (and Peter isn't too keen on Christmas anyway), the 'Busters ignore them...and then find out that their interference changed the past so that everyone hates Christmas the same way Scrooge did.
- Weird Crossover: This episode crosses over with A Christmas Carol — a cartoon that's a blend of sci-fi, comedy, and horror crossing over with a classic novel.
- Wham Line: After Ray and Winston ask if Scrooge will reform, the Ghost of Christmas Past drops a line that changes what the audience (and the guys) have thought was going on.Ghost of Christmas Present: I think he'll learn his lesson, [to Peter] as I assume you, too, have learned yours. That is, of course, why you're here.
- Wing Ding Eyes: When Janine says she'll help for Egon's sake, hearts appear in her eyes.
- Yet Another Christmas Carol: Played with in that it involves the actual Christmas Carol story — the Ghostbusters accidentally trap the Ghosts of Christmas, so Egon has to bring them back and the rest have to impersonate them.
- You Are Too Late: After realizing they've changed history, the others race back to the firehouse to try to stop Egon from putting the ghosts in the Containment Unit. They get back just after he's finished.
