Right before a visit from an influential hotel reviewer, Mavis lures an unwanted guest into the hotel. Mavis finds her childhood doll, Demented Debbie, who continues to be her best friend forever.
Mavis wants to prove she can care for a living creature by rescuing a bad egg. The kids try to watch the last episode of their favorite show, Hotel Pennsylvania.
The hotel hosts Lydia's favorite author but the kids cleaned the room so fast they accidentally got rid of a ghost writer. Hank wants to be all one piece and not stitched together.
Cornelius Shivers is at the hotel writing a book about the wonders of the monster world, including the hotel. When a priceless heirloom is destroyed, the four kids are the prime suspects.