Mirror: A Tale of Twin Cities (traditional Chinese: 鏡·雙城; simplified Chinese: 镜·双城; pinyin: Jìng·Shuāng Chéng) is a 2022 Chinese streaming television series adapted from the Chinese fantasy novel Mirror: Twin Cities written by Cang Yue. The series was directed by Patrick Yau and starred Li Yifeng, Chen Yuqi, and Zheng Yecheng. Set in a fantasy world named Yun Huang (云荒), the story tells of young heirs from Quan Xian and Kong Sang tribes, fighting for the freedom of their people. The series began airing on Tencent Video and Youku from January 16, 2022. A prequel series, The Longest Promise, premiered on July 2, 2023.