Peter falls ill, and Louis asks a doctor (Stanley Ralph Ross) he met two days ago to come and take a look. It turns out the doctor has sent them potato chips, which makes people allergic to ghosts, and only Peter has eaten enough of them. The doctor gives them more chips. What the Ghostbusters don't know is that the doctor is a ghost and they have to develop resistance to the allergy.
A confrontation with a giant clock monster causes Egon to become younger and younger. The catch- they only have until midnight, at which time the now infant Egon will vanish from existence forever.
The legendary and apparently ghostly Sherlock Holmes and Watson arrive in New York to find Professor Moriarty. When Watson gets captured, Sherlock Holmes selects Winston to help him. Moriarty seeks to absorb all the ghosts in the containment unit.
The Ghostbusters are called to stop a witch that has been terrorizing the town of Lewiston. She wants revenge against the descendants of those who imprisoned her 300 years ago, which includes Egon.
A year after the Ghostbusters defeated Vigo the Carpathian, a ghost named Poso kidnaps Janine and Louis to force the Ghostbusters to hand over their business. The Ghostbusters get help from a recently-captured ghost, Shifter, to find out why Poso wants their business and where to find him. Covered in mood slime, Peter goes to the Ghost Town to save Louis and Janine.
The Ghostbusters get a new TV as payment for a job. When Ray stays up to watch television, he sees into the Ghostbusters' future. The others don't believe him at first, but Ray is quickly proved right and the next vision shows them their deaths.
The Ghostbusters are tricked into letting their guard down and get captured by ghosts. They're charged with crimes against ghosts and stand trial. It's up to Janine, Louis and Slimer to save them from a horrible punishment.
The Ghostbusters are on live TV at the tomb of Al Capone (Jocko Marcellino) where his ghost is supposed to appear at midnight. Something does happen and the guys get transported to the other side, getting involved with Al Capone and other supernatural criminals.
The Ghostbusters are confronted by Crowley (Michael Rye) and his group, who want their help in ending Halloween. The guys turn him down, but one of their PKE meters is stolen and used by Crowley to accomplish his goal. Unfortunately, all he does is break a seal, opening our world to numerous ghosts – including the huge, rampaging Boogaloo (Brian O'Neal) – and giving the Ghostbusters a lot to handle on Halloween night.
After being hit by Egon's experimental proton ray, Peter becomes something of a superhero, as his muscles grow and he becomes a buldging muscle hunk with powers, but it won't last long.
A bad lookalike of Slimer on the run arrives in the firehouse via a mirror and sends Louis and the real Slimer to the Ghost World.
A family of ghosts on vacation work to remove those they believe are interrupting their peace and quiet, including Peter, Winston and Slimer.
The Ghostbusters become involved in the world of knights and dragons to free a captured Janine.
Slimer finds a cat that can make all of his dreams come true.
Slimer wins the lottery, only to find his winnings have been cursed.
The Ghostbusters get a temp (who turns out to be a ghost) and she decides Egon would make a great husband.
The firehouse is going to be torn down to make way for a new expressway, but that's the least of the Ghostbusters' problems. The guys and Slimer get sent back to 1959 due to a trap accident. They have to find a way back and fight ghosts without their equipment.
A trio of ghosts abduct Slimer and will keep him unless the Ghostbusters agree to free a ghost named Spiderlegs.
The Ghostmaster is back and casts a spell on the Ghostbusters that causes all electronic equipment near them to shut off, including their proton packs and ghost traps.
Slimer breaks a trap and doesn't completely fix it before the guys use it on a job. Now the essence inside starts to leak out and make inanimate objects come to life.
Stuck on a train, the Ghostbusters have to play games to bring it to a halt.
