Tommy Frazer's just moved to a new town, and a new school. A school that's so big, it's easy to get lost in. One day, Tommy does indeed get lost, and stumbles upon a room dedicated to the Class of '47, who all disappeared mysteriously after getting their class picture taken. Later, the night of a school dance, he and his friend Ben find an elevator that goes sideways, leading them to the truth about the missing students.
The book provides examples of:
- And I Must Scream: An entire class has been teleported to a strange black and white world where they never age. When Tommy and Ben arrive here years later, most of the students have devolved into insane, bloodthirsty savages, and want to keep them there forever.
- Chekhov's Gun: Tommy's lighter and Thalia's lipstick, which help them escape Grayworld.
- Cruel Twist Ending: The kids escape Grayworld, only to find out that their class photo will be taken by Mr. Chameleon, whom they realize too late was the photographer who sent the Class of '47 to Grayworld in the first place.
- Deliberately Monochrome: The Grayworld is a dimension without color.
- Downer Ending: The protagonists escape Grayworld with help from Thalia, but can't save her and the other trapped students. They return to the school dance in time for a class picture, where they discover way too late that the photographer is the same one who sent the class of 1947 to Grayworld. He snaps the picture, presumably trapping them for good and stealing Bellwood's children all over again.
- Fate Worse than Death: The main characters end up trapped in an alternate dimension with no color, where you never age.
- Foreshadowing: Tommy reads a Ray Bradbury story about "these kids who live on a planet where it never stops raining," and are miserable because they can't go outside in the sun. This general idea of kids being sad they can't experience sunshine becomes similar to the Grey kids, who are stuck in the grey world with no natural sunlight, and are sad about it.
- Greater-Scope Villain: Mr. Chameleon, the sinister photographer who sent the children to Grayworld in the first place. Even worse, he's still alive in the present day.
- Magical Camera: Mr. Chameleon's camera acts as a portal to another dimension.
- Mythology Gag: The picture of the skull on the back of the locker as seen in the cover is Curly the Skeleton.
- Never Trust a Title: Despite having the word "haunted" in the title, the book doesn't involve ghosts of any kind.
- Nothing Is Scarier: Mr. Chameleon is, judging by the impact of his actions, one of the most horrific characters in the series. We never actually meet him, or learn who or what he is or why he's sending children to the Grayworld.
- "Ray of Hope" Ending: The ending implies that Tommy and the kids in his class will be sent to Grayworld by Mr. Chameleon and trapped like the 1947 class was. However, Thalia can just as easily open another doorway into the color world using her lipstick if it still has its color by the time Tommy and the others show up. And even if it doesn't, Tommy can most likely burn open a doorway using his lighter, or any of the many other kids in their class can easily have an object that can allow them to open a doorway.
- Sanity Slippage: Most of the kids from the original class of Bell Valley Middle School went completely insane ever since they were trapped in Grayworld.
- Uncanny Valley Makeup: Thalia wears such heavy makeup that she looks completely unnatural and even creepy (she is only twelve years old), leading to bullying from her classmates. It turns out this is because she escaped from the colorless world and her skin is completely gray.