Roger Livesey ("Paul") is the wealthy but rather indifferent dad to "Dick" (Anthony Newley). The youngster hates the idea of going back to his boarding school, but his skinflint of a father is having none of it. When "Dick" tries a bit of emotional blackmail, his dad - clutching a mysterious stone from a temple in faraway India finds himself making a wish and now has the mental age of his son. His son, seeing an opportunity for some mischief takes hold of the sto...