Monica Anderson thinks her biggest problem is taking her karate-chopping younger brother, Peter, trick-or-treating on Halloween. But she is wrong. After knocking on the door of an old, creepy house the kids are met by a strange woman pleading for their help. The evil Dr. Screem is after five horribly ugly ancient masks. These artifacts have the power to manipulate the world around them. Monica and Peter don't want to help, but they must retrieve the masks and defeat Screem. Unfortunately, nothing on Halloween is what it appears to be.