Normally, when two young lovers announce their impending nuptials, their parents are beaming with pride. But when the children of two warring families announce their plans to marry, the fathers literally freak out -- and panic. As it turns out, there's a slight possibility that the lovebirds could be brother and sister, thanks to a suspected mix-up at the local hospital. But no one's quite sure how to break the news to the couple. ....