Jackson Gerard and Jillian Gerard get strange powers from an odd fortune telling machine. It seems fun at first, but now an evil man Inspector Cranium wants that power and will do anything to get it. He is head of The Institute, which hunts down anyone with powers. These two children, Arnie and Nina invited them to their birthday party. When the party is over, Artie and Nina, want to show them something. But Inspector Cranium shows up. Jillian and Jackson think he is looking for them, but he is actually looking for Artie and Nina. The children explain that they have powers too and that they pretend to be gross so they will not be found. Inspector Cranium tries to capture them, but Jillian and her brother will not allow that. The children all use their powers and Inspector Cranium is turned into a baby. The next day, Jillian and Jackson go to Artie's and Nina's, but the place is empty. The twins figure the twins have to keep moving.
After those events, the twins get invited to be Very Special Guests in HorrorLand. When they go in, they find the same Madame Doom fortune teller booth at the mall. They find Inspector Cranium and he starts chasing them. They lose him in the Doom Slide, but the monster police come to take them to the keeper a.k.a Dr. Maniac. When they go in, they find other children in there sad. Then a raging purple rage jumps around and turns to slimy goo. It gets too cold and a boy (Robby Schwartz) gets cold and freezes to death. Jillian reads his mind and realizes it is a trick! She pretends Dr. Maniac killed him. The crazy villain gets very upset, because he thinks the horrors are going to do something to him. So he flees, leaving the door open. Robby ask how she knew that so she answered she could read minds. The guest flee to search for mirrors.
When they find the mirrors, Carly Beth Caldwell tells them to make a line. She starts calling names: Billy Deep, Sheena Deep, Boone Dixon, Sabrina Mason, Abby Martin, Molly Molloy... one by one they all disappeared. Jillian was amazed. The Monster Police catch them. They try to jump in the mirror at once, but the mirror turns to hard metal so they decide to make a run for it. Then they find two siblings named Luke Morris and Lizzy Morris spying on them....