A bat named Bitewing flies over to Cacklefur Castle, where he is greeted by Creepella von Cacklefur. Creepella is thinking of an article for The Shivering News, already having the title "The Secret Life of the Ghosts of Mysterious Valley". After she got dressed and ate breakfast, Grandpa Frankenstein gives her the idea to go to Squeaksptteare Mansion, which is rumored to be inhabitated by ghosts.
She brings her niece Shivereen and Bitewing and drives off to Squeakspeare palace. They soon find a tail sticking out from behind a pile of suitcases, and, believing it to be a ghost, pulls it. They find out that the "ghost" is really a timid mouse named Billy Squeakspeare. Billy has moved into the mansion but every time he enters he is pushed out by an unknown force. Creepella decides that if they all went in, the ghosts wouldn't be able to push them all out, and drags Billy into the mansion.
They find a secret passage in the mansion. They go into the secret passage, leading them to a maze. Bitewing leads them through the maze, and they find themselves in front of a door with a sign that says Linen Closet that opens by itself, where they find a table covered by a huge sheet. Much to Billy's objection, Creepella pulls it off, revealing twelve ghosts: Simon Snootysnout the butler, Bob Woodmouse the carpenter, Miss Dustmop the housekeeper, Hank Hammerat the blacksmith/locksmith, Bonnie Ragu the cook, Ted Trimmertail the gardener, Ned Needles the tailor, Dreamella Airhead the maid, Gus Sip the caretaker, Leggy the spider artist, Buzzilla the toothless mosquito, and Arf the sleepwalking dog.
The ghosts demand that they leave the mansion, with Billy so scared that he agrees immediately,
but Creepella tells him that he has the right to live here. When Billy explains that he simply wants a place where he can write peacefully, the ghosts are excited, having wanted a writer in the mansion for a century. Simon says that they will let him stay as long as the thirteenth ghost agrees. The thirteenth ghost turns out to be Billy's great-great-great-uncle William Squeakspeare. William assumes Creepella is Billy's girlfriend and that they are getting married, much to Billy's dismay. After Creepella writes down the jokes William tells them, Billy finally moves into the house, but is annoyed to find that the ghosts have a bad habit of cleaning the mansion at midnight, thus leaving him sleepless nights.
Creepella puts the article on The Shivery News, with it being such a success that she makes it into a book. She needs someone to publish it first, and decides Geronimo will do it. Geronimo publishes the book and it is a huge success, with everyone asking when Creepella's next book is coming out. Geronimo can't answer the question, and soon gets a call from Creepella, asking if he likes her story. Geronimo has to admit even he enjoyed the story, saying it is a very strange but thrilling bestseller.