On Halloween Slimer and Fred head out to collect bags of goodies, but unbeknownst to them, Professor Dweeb teams up with Goolem and Zugg in a plan to get rid of Slimer.
In an attempt to make life simpler at the Hotel Sedgewick, Slimer, Fred and Bud manage to get Grout transferred to a ritzy, uptown hotel, but soon madness reigns as Professor Dweeb becomes the new manager.
At the firehouse Slimer attempts to wallpaper the kitchen in an effort to please the Ghostbusters, but Dweeb and Elizabeth are intent on stopping and capturing him.
Fred receives an invitation from Slimer to join the gang at the firehouse for a barbecue, but Morris Grout has hired Bruiser, guard dog extraordinaire.
A mouse appears in the firehouse, and Slimer must help the poor little rodent survive by thwarting all of Manx's efforts to exterminate his new friend.