Nikki's diary describes a frightful Halloween, on which she helps with her sister's ballet class party at the same time she is Brandon's date for their middle school Halloween dance, where she has promised to spend the evening with her two best friends.

On his way to visit his aunt Sweetfur who is on vacation in the Pleasant Paw Hills, Geronimo Stilton--editor of "The Rodent's Gazette"--gets lost in a dark forest and seeks shelter in a run-down mansion unfortunately haunted by cats.