House of Horrors (A Weirdville Book). Weirdville, #2

When her parents allow her to go to the fair, Jacky is over the moon. The fair is most famous for its haunted mansion, the House of Horrors, and her friend Ben can't wait to try it out. Her best friend, Cass, is a little more reluctant, but then again, Cass has always been a chicken when it comes to getting scared. Jacky and Cass are determined to act tough, so when Ben suggests they try out the House of Horrors, the girls tag along, even though the place gives them the chills.
As soon as the three of them enter the spooky monstrosity, the ride comes to a screeching halt, and the horror begins. The lights fade, and a hooded figure appears and tells them they're stuck in a twisted game of cat and mouse. He will show them their worst fears, and if the kids manage to face down those fears, they'll have a chance of getting out of the House of Horrors alive. If they don't, well....
Thirty minutes to go. Thirty minutes to face their nightmares... and the clock is ticking.