In the legendary Nine Cities, Fan Yun, a poor young lady from a distinguished family, and Qi Zheng, the lord of Bai Qie Hei City, progress from testing each other to mutual trust. Together, they overcome obstacles for the people's benefit, ultimately finding both friendship and love; Fan Yun also helps Qi Zheng to bring peace to the realm, break old conventions, resolve the crisis of the Nine Cities, and work together to build a prosperous Nine Cities. 

The series is adapted from Saori Yukino's "The Tale of the Kingdom of Clouds."