The Ghost Busters must stop the Fat Man and Rabbit from summoning the ghost of gangster Big Al Caesar, who will help them steal the stuff dreams are made of: the Maltese Monkey.

Dr. Frankenstein returns, seeking the brain of the world's most gullible fool to transplant into his Monster. Enter Eddie Spencer.

Jewel thief Mr. C schemes to scare Carola out of the castle so he can find and steal the Canterville Diamond, not realizing it hangs around the neck of the scaredy-cat ghost of Sir Simon de Canterville.

Hoping to remove the curse of the werewolf from hapless Harry Albert, Gypsy fortuneteller Sophia comes seeking to steal the Baldus Lupus Amulet that Spencer recently unearthed.

Scroggs schemes to shanghai the unsuspecting Spencer and Tracy to serve as deck hands aboard Cap'n Beane's Flying Dutchman ghost ship.

The Phantom of Vaudeville, a masked ventriloquist with his dummy Elmo, seek revenge after suspecting Spencer, Tracy and Kong of being the song and dance act that upstaged them decades earlier.

The Ghost Busters become embroiled with Egyptian Queen Forah and her Mummy as they search for the ape-sorcerer Simios, who in turn can bring them to Spen-Zah, possessor of the secret of immortality.

The ghost of a 17th century witch and her stooge Gronk return for revenge on the descendant of the Edward Spencer who broke her spell at the Salem Witch Trials.

Those ghostriders in the sky are the spirits of Billy the Kid and Belle Starr back to round up a new gang of cattle rustlers. The Ghost Busters disguise themselves as cowboys to get the Dematerializer drop on 'em.

The Ghost Busters may get the bite put on them when Count and Countess Dracula return from the other side in search of a warm-blooded donor.

Dr. Jekyll and Mr. Hyde are living as two separate persons, with the Neanderthal Hyde driving insane the urbane Jekyll. Only by drinking a potion made from a person without any personality can Jekyll ever hope to be set free from Hyde.

The Ghost Busters discover the Red Baron and his grease monkey Sparky using the haunted castle to repair their damaged airplane.

The ghosts of Erik the Red and Brunhilda return to plant a Viking banner and establish their claim to having discovered America prior to the loathsome Lothar the Hun.

Merlin and jester Gronk are pursued from the Great Beyond by their nemesis Morgan Le Fay, who intends to trap them in this era. The Ghost Busters befriend and assist the broken-down magician in his battle with the beautiful sorceress.