His mind was 81. His body was 18. When Jack Watson found his fountain of youth, it overflowed with comedy! Jack Watson (George Burns) is a swinging 81-year-old bachelor who loves big cigars and busty women. His grandson David (Charlie Schlatter) is a shy 18-year-old dweeb bullied by his classmates and ignored by the girl of his dreams. But when Jack and Charlie are involved in a freak birthday accident, they discover that their souls have now switched bodies. Can David turn his life around with some help from Jack's confidence and style, or will a desperate family decision destroy their futures forever?