When Eerie Elementary plans a big celebration for Eerie Day, the spirit of the evil scientist Orson Eerie wants to use this as an opportunity to take over the school, and intrepid hall monitors Sam, Lucy, and Antonio must stop him., Eerie Elementary is planning a big Halloween-type celebration for Eerie Day, including hosting a "haunted house" at the school itself; but the spirit of the evil scientist Orson Eerie sees this as the chance to finally triumph over the intrepid hall moniters, Sam, Lucy, and Antonio--and it is up to them to prevent a catastrophe and perhaps even defeat Orson and banish him from the school forever.