On the front porch of an eerie old building, a man plays the clarinet and then vanishes. Meanwhile, it's stormy, and the Ghostbusters are driving to one of Egon's events, but Peter is sulky and wants to fly instead. Ray reads a manual that says the hotel is a perfect vacation spot, but when they get there, they find it's the tumbledown building from before. However, Peter cheers right up when a young blonde woman shows up and shows them to their room.
At midnight, ghosts play music, and then Ray wakes up and walks off in a weird trance. Egon supposes Ray is possessed, so they follow him out. Outside, they see more people who seem possessed, and Egon detects "discontinuity" in the space-time continuum. The surroundings start to change to how they were in the past, and Egon doesn't like this, but Peter just sees it as a party and starts dancing. The blonde lady throws powder on the ghosts, making them disappear, causing time to revert to normal and everyone snaps out of their trances.
She explains that the leader of the band is a ghost named Malachi, who played the trumpet in life and can control people with his music. Peter asks why Malachi is controlling people, and the woman explains that he was famous back in his day, so wants to turn back time, which can happen if he plays the music often enough, then explains that she's a voodoo priestess but is still less powerful than Malachi.
They have Janine send their tools over, then head out, with Egon explaining that if Malachi wins, time might stop altogether. Malachi and his band start playing music again, making time revert again. Civil war soldiers then show up, then the ground turns into ocean (since they've been sent back to before Louisiana, which is where the hotel is, was on land). Then, an aggressive Megaladon shows up and they start swimming for their lives, but luckily time reverts to the present.
They plan on stopping Malachi, but then Winston reveals that the equipment was accidentally shipped to Hawaii. So they drive off to a place that has a lot of tech and Ray builds some makeshift machines for trapping Malachi. He tries to do it, but the "proton pack" explodes (luckily, Egon realises it will happen and gets Ray to take it off). Egon, however, has a Plan B: compose and play a tune with the right vibrations to stop Malachi's music.
Malachi starts playing music again, so the Ghostbusters start playing their tune (having chosen rock for its "primal and powerful" nature). It works, and then Peter leaves for Mardi Gras, not realising it's over.
This episode provides examples of
- Battle of the Bands: A literal example — the Ghostbusters and Malachi's band literally fight with music.
- Delayed Reaction: It takes the Ghostbusters and the priestess, but especially Peter, a while to realise they're no longer in the ocean.
- Demonic Possession: Subverted — when Egon sees Ray acting oddly, he thinks he's possessed, but really it's the music that's controlling him.
- Flashback: We see a scene of Malachi in life as a jazz player.
- From Bad to Worse: First, time starts reverting again... then, it reverts back to the Civil War... then to before Louisiana was on land... then a Megaladon pursues them.
- Godzilla Threshold: Ray's makeshift machines are hastily built and they don't know if they'll work, but as the priestess points out, they have to do something.
- Hope Spot: The makeshift proton pack almost works, but then blows up.
- Immediate Self-Contradiction: Peter calls the town "grungy" and "boring", but then when he realises the priestess is listening and hastily switches to compliments, one of which is "fascinating".
- Layman's Terms: Egon explains what he thinks is wrong with Ray in Sesquipedalian Loquaciousness. Peter says, "What did he say?", and Egon says, "I said he's possessed!".
- Lost Food Grievance: Janine yells at Slimer for eating her donut.
- Magic Music: Malachi's music can control people's minds. Downplayed for the music the Ghostbusters play to stop it, in that it's the vibrations that do the dirty work rather than the fact that it's music.
- Mass "Oh, Crap!": Everyone becomes scared when the Megaladon shows up.
- Mondegreen Gag: When the woman says she's a "mambo", Peter thinks she said "mama".
- Oh, Crap!:
- During the first "party", Egon says nervously, "Uh-oh!", then Peter and Winston too get nervous (knowing that it always means trouble when Egon is scared).
- Egon gasps when the historical soldiers show up.
- O.O.C. Is Serious Business: Egon is hard to scare, so Peter and Winston get nervous when he says, "Uh-oh!".
- The Power of Rock: The Ghostbusters play rock and roll music to stop Malachi, channelling into how "primal and powerful" rock is. Justified, since music causes vibrations, which are what's needed to stop Malachi.
- Running Gag: People keep referencing Mardi Gras.
- Skewed Priorities: When Malachi first plays his magic music, Peter just wants to party, not caring that things are reverting to how they were in the past, and several people, including Ray, are entranced and suspected possessed.
- Speak in Unison: When Winston reveals the proton packs and ghost traps are in Hawaii, Peter and Egon echo back, "Hawaii?!" at once.
- Tempting Fate: Ray says the hotel is perfect, but when they get there, it's falling apart.
- This Is Gonna Suck: When Peter says, "I don't wanna hear that, Egon!", and then the soldiers show up, he adds, "I don't wanna hear that either!".
- Time Travel Episode: The villain of this episode can turn back time.
- Vacation Episode: The episode shows the Ghostbusters on vacation in an old hotel.
