The Bagge Family arrives in New York City. Muriel has won a sitar contest and her prize is to perform at Radio City Music Hall. At the theatre they are welcomed by a giant, creepy insect who calls himself Schwick (not under any circumstance may anyone call him "Buschwick"). He poses as a stage hand and promises Muriel her own rehearsal room and Eustace hotdogs.
Schwick show them to the "rehearsal room," a scary, musty room littered with shackles and human remains. There is an unseen threat living in a mouse hole in the room that is responsible for the demise of previous of the theatre's stars. The argumentative Schwick sends Courage out to get a package and orders him to hurry up, or else "It's curtains for the sitar lady". And Courage is instructed to keep the police out of the picture.
Courage tries to find the house where the package is waiting, and is snatched by the evil mattress delivery wagon, and dropped off the block of a flat owned by Schwick. It is condemned, yet inhabited by several monsters and unseen residents behind sealed doors screaming to be released. After retrieving the package, that is labeled Evil from an unseen, violent instance, Courage flees the scary abandoned apartment building and jumps on a subway train. A policeman, who is searching for the evil package, has followed Courage and asks him to show his license.
The railroad engineer is so terrified by the sight of the evil package he flees the train. Courage tries to take control, but unfortunately steers the train into the theatre's rehearsal room, where Muriel is still practicing. Schwick takes the evil package. It contains nothing more than a window squeegee, that Schwick needs to wipe away the cry for help written on the grimy window. However, the train collision has broken it. The bug is infuriated, and now opts to unleash the rehearsal room monster. Courage panics and carries Muriel up to the stage, where she performs. The police officer from the train has called for backup, and arrests Schwick. Schwick turns out to be wanted fugitive, and obviously not a real stage hand.
- This episode won the "Best Sound Editing — Television Animated Series — Sound at the 2001 Golden Reel Awards."
- When Courage enters the building, one can clearly make out a man shouting "Open the door!"
- King Ghidorah was one of the monsters living in the apartment building.
- The Rat and Weasel from The Demon in the Mattress make a cameo in this episode.
- On Cartoon Network Asia and Philippines, the scene were all the three monsters were edited out, possibly to remove the disturbing parts of the episode, despite there are no complaints from parents that the kids were scared on this episode.
- The three monsters were shown during the Powerhouse era until (possibly) the New Wave era. On New Wave era and the early CHECK it 1.0 era, it has been reduced to the Violin Girl door instead. On the middle of the CHECK it era (around 2013 or 2014), the three monsters were edited out.
- Although Eustace supports briefs over boxers in this episode, he is mostly seen wearing boxers in other episodes.