Gifted pupil, Oswin boards with his cousins in a spooky Edwardian house. His favorite cousin, Gemma, thinks it may be haunted, but her loud-mouthed, older sister, Beryl, insists that there is no such thing as ghosts! When Beryl talks of having Gemma sectioned under the mental health act, Oswin decides to prove her wrong, to prove that ghosts do exist and that their house is haunted. He builds some nifty gadgets and gets Gemma to keep an accurate recording of her ghostly experiences. Despite Beryl's constant interfering, they begin to gather evidence that there is indeed paranormal activity in the house...