The Scream of the Haunted Mask

The Scream of the Haunted Mask was the fourth book in the Goosebumps HorrorLand book series. It was preceded by Monster Blood for Breakfast! and followed by Dr. Maniac vs. Robby Schwartz.

Plot
Menaced by the scream of the Haunted Mask, Carly Beth Caldwell starts to delve into its past - searching for a way to escape it. She uncovers a terrifying tale about an old stable she works near, but the mask is not the only threat. At HorrorLand, she and her friend Sabrina Mason attend a magic show. There, they team up with Billy Deep, Sheena Deep, and Matt Daniels. Then they overhear a disturbing plot to dispose of them all.

Trivia

 * Apparently, this book is a retcon. The Haunted Mask II never happened. Carly Beth is twelve in this book, just like in The Haunted Mask II.