Billy and Sheena go with their Uncle, Dr. Deep, to search for treasure and are pursued by pirates who have been dead for two hundred years, and when Billy and Sheena return to land and visit Horrorland they encounter their worse fears.
What should Carly Beth be for Halloween this year? Terrified! Late at night, and ugly green mask is mysteriously calling out to her. If Carly Beth survives the night, even a scary theme park might sound like a vacation. Or maybe not! At Horrorland, every night is Halloween. And those monster masks? They aren't masks at all.