Two young couples on a double date go to a mysterious carnival. As a prank they decide to spend the night in the funhouse. When they witness a brutal murder, they suddenly find themselves in horrific danger.

Four teenagers, Amy Harper, Buzz Klemmet, Richie Atterbury and Liz Duncan, travel to the carnival which has just come to town, for some fun. As the night begins to come to an end, Liz suggests they stay the night in the fun house. They all agree and decide to take the last ride before the attraction shuts down. As they stay in the fun house, the four witness and horrific murder against a psychic reader by a very big man in a Frankenstein mask, also Richie takes some of the money earned by the man who runs the fun house. The owner is furious about the missing money and sends his son, Gunther, who killed the reader, to take care of the thieves. Now the four are locked in the fun house, being stalked and killed one by one.