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.

Matt Daniels battles a mysterious substance called Monster Blood that makes things grow, and then visits HorrorLand amusement park, where some of his friends disappear.

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.

"Jillian and Jackson freak out when they suddenly can read people's thoughts. But the trick turns to terror when the twins are stalked by a strange scientist who wants to know exactly what's on their minds. Will the twins ever lead normal lives again?"--Back cover

Julie begins to suspect that HorrorLand is not all fun after she is attacked by a giant spider.

Boone and Heather are going to summer camp, with man-eating snakes and disappearing campers. Things get worse when Boone joins eleven other guests at Horrorland because something's wrong with the bumper-car ride called the R.I.P.P.E.R.

Jessica and her best friend, Ryan, find the perfect HorrorLand souvenir --a two-headed coin with mysteriously dark powers. After an unlucky flip of the coin, they find themselves in a strange land being chased down by angry guards. HorrorLand was scary but this is much worse. Will they be able to escape?

"Ray Gordon loves to scare his younger brother, Brandon. It's not hard considering Brandon is terrified of everything--loud noises, roller coasters, and especially the wooden dummy, Slappy, that Ray got from Jonathan Chiller's HorrorLand gift shop. In order to throw his big New Year's Eve party, Ray's parents make him promise to leave Brandon alone. But strange, mean-spirited things keep happening to his little brother, and Slappy always seems to...

Twelve-year-olds Andy and Marnie, having enjoyed a day at Horrorland and received a gift souvenir from the Chiller House, take home a wish-granting hounds tooth which is supposedly haunted and soon learn that nothing is ever really free.

"Mickey is put in charge of his vacationing neighbors' cat, Bella. His best friend, Amanda, comes along to help out. All they have to do is make sure Bella has enough to eat and doesn't destroy the furniture. Seems simple enough. But Bella escapes from the house and is hit by a truck. Mickey feels awful. What is he going to do? Amanda has an idea to replace the cat with a look-alike from the local pet store, Cat Heaven. They find a cat that looks...