On her wedding day, Shen Tangning is framed by her family and her fiancé, Xie Linzhou, and exiled to the bitterly cold Snow Pass in the far north. Relying on the northern frontier records left behind by her mother, she leads her fellow exiles in their struggle to survive, improves their barracks, extracts salt, and builds a city. She joins forces with Xiao Zhaoye of the Northern Frontier Army to repel foreign enemies and gradually uncovers the truth behind an old military provisions case. After clearing her name, she refuses the honors offered in the capital and stays at Snow Pass to build a city and bring peace to its people, becoming the City Lord Shen who protects the northern frontier.