Cast
Plot
It is cleaning day at the Firehouse. Slimer is left in charge while Janine goes out to buy groceries. A rotund mouse named Mousey bursts through the doors and straight through Slimer's stomach, hotly pursued by a hungry cat named Manx. Slimer takes Mousey under his protection and the episode becomes a series of escalating traps: Manx sets out rubber cement bait with cheese, paints fake mouse holes on the walls, and tries to vacuum Mousey out of his real hole. Slimer counters each scheme, including turning the vacuum back on Manx and launching him out a window. Janine returns, congratulates Slimer, and treats him to ice cream, unaware of the chaos. Manx, hiding in a nearby van, throws a tantrum at his defeat, only to discover the van belongs to the City Dog Pound.
Trivia
- There are technically two versions of this episode, differing only in the title card. One reads "A Mouse in the House" and the other reads "Mouse in the House". The Real Ghostbusters: Complete Collection DVD box set contains both versions.
- A partial calendar visible in the scene where Manx paints fake mouse holes ends at 30, consistent with a September 1988 calendar. The next episode in DVD order, "Cash or Slime," takes place on October 6, 1988.
- Slimer befriends a mouse again in the The Real Ghostbusters episode "Spacebusters."
Animation Notes
The Firehouse design and layout were not fully taken into account during scripting and storyboarding. The action is assumed to take place in a back room beyond Peter's office area. However, when Manx rolls out a window inside the rubber cement ball, the exterior background implies a much greater drop than the Firehouse layout would support.
Quotes
"A ghost's work is never done."
Screen Caps

References
- Ghostbusters Wiki, "A Mouse in the House"
- Spook Central, "Slimer! Episode Guide: A Mouse in the House"