唐太宗寵愛才人武媚娘，媚娘卻與太子李治（袁報華飾）互生情愫。太宗病危，臨終前命媚娘出家為尼，李治承諾三年後接她回宮。永徽五年，媚娘（湘漪飾）回宮並封為昭儀，王皇后遂籠絡媚娘以對付蕭淑妃，媚娘卻施毒計剷除兩人，順利獲封為后。

媚娘極力剷除異己，並代李治處理國事，她又重用上官婉兒（陳琪琪飾）及武承嗣（黃百鳴飾）等人，積極栽培親信。李治死後，李哲（艾迪飾）繼位，媚娘繼續把持朝政，更把李哲廢掉，最終她竟自立為皇，改唐為周。

張易之（蔡雲飾）與弟獲媚娘寵愛而權傾朝野，承嗣又覬覦太子之位，幸而狄仁傑成功說服媚娘重立李哲為太子。張氏兄弟謀反，媚娘拒絕制裁二人，忠臣們遂扶助李哲平亂，決意恢復大唐國祚。

During the Tang Dynasty, Emperor Taizong favored his concubine Wu Meiniang. She fell in love with the crown prince Li Zhi, and the emperor asked her to become a nun before he died, with the promise that Li Zhi would bring her back to the palace in three years. Wu returned as the Empress Dowager and eliminated her rivals. After Li Zhi's death, Wu continued to control politics, even deposing his successor, Li Zhe, and proclaimed herself as the first female emperor, changing the name of the dynasty to Zhou. With the help of loyal ministers, Li Zhe was eventually reinstated, and the Tang dynasty was restored.