It's Halloween and Monica Andersen is going trick-or-treating! Together with his younger brother. They knock on the door of an old, creepy house and meet a strange woman who begs them for help. Every year she is forced to battle the sinister Doctor Krikk for control of five sacred masks. These artifacts give their owner power over the world. At first Monica is reluctant to help, but soon Krikk breaks into the house and steals the masks. Now she and her brother face a mission that will change their lives forever!