Plot
While Slimer fools around with the Firehouse photocopier, Louis Tully arrives with a stack of tax forms he needs copied and mailed by 5 p.m. Frustrated, Louis heads for a copy store and leaves Slimer alone. Three ghosts named Grub, Larvy, and Mopes slip in through the alley and descend to the basement, where a captive at the Containment Unit's porthole points them toward their boss, Spiderlegs. Their attempt to release her trips an alarm and nearly sends the unit critical, but Slimer remembers to hit the reset button. The trio grab Slimer and order him to open the unit. He refuses, and they carry him off to their hideout, where he discovers the walls are ghost-proof.
Back at the Firehouse, Louis finds a ransom note as the Ghostbusters return from a case: they have until midnight to release Spiderlegs, after which they are to signal the kidnappers by requesting a particular song on the Moon Man's radio show. With the lead ghost gone to listen to the broadcast, Slimer manipulates his two guards into feeding him the entire contents of the refrigerator and then talks them into a game of tag.
At the Firehouse, the team pulls Spiderlegs' file (where her name is misspelled "Spiderless") and Egon reasons that they can locate Slimer by finding the frequency at which his ectoplasm resonates and tracking it with sound waves. Louis recalls the slime Slimer left on the copier, which gives them a sample to test. They isolate the frequency, record it to tape, and arrange to have it broadcast on the Moon Man's show alongside the requested song.
The frequency hits Slimer in the ultrasonic range and sends him resonating out of control, wrecking the hideout. Peter and Winston, aboard Ecto-2, spot the only building shaking in the Washington Square area and radio Egon and Ray, who drive over in Ecto-1. The Ghostbusters corner the panicking ghosts, and Slimer helps capture Grub, Larvy, and Mopes in a trap. Back home, the three are deposited into the Containment Unit, where an unhappy Spiderlegs chases after her henchmen.
Production
The episode carries the production number 201016.2 Recording took place over two days in July 1989: Dave Coulier and Rodger Bumpass recorded on July 17, and Frank Welker, Maurice LaMarche, and Buster Jones recorded on July 19.2
The Containment Unit porthole seen here first appeared in the Slimer! episode "Don't Tease the Sleaze," making this the first regular The Real Ghostbusters episode to use it. It marked an early case of an element introduced in the Slimer! segments being folded back into the main series. Janine Melnitz does not appear in this episode.
Release
In broadcast and DVD running order, "The Ransom of Greenspud" follows "It's About Time" and precedes "Revenge of the Ghostmaster." It was collected on Volume 4, Disc 3 of the complete-series DVD box set.
