Stormy Evening.
Si is pregnant and is planning to marry Chow. Both families meet and discuss this issue in a thunderstorm evening. Although incidentally knowing that they are siblings, they insist to get marry. A thunderbolt changes everybody's mind. Si and Chow now try to escape being forced to marry. At this time, another thunderbolt hit them...
四鳳珠胎暗結，準備與男友周萍結婚。雷雨交加之夜，雙方家長見面談婚事，才發現二人原來是同母異父的兄妹。周萍和四鳳仍堅持要結婚，周萍之父朴園拒不接受。兩家人尋求解決方法之際，卻發現朴園與妻子繁漪有不可告人的秘密。各人遭受雷擊，想法轉變。周萍與四鳳怕被他們迫婚，離家出走。二人為救朴園，再被雷擊，最後……
