A hundred years ago, in Daying Qi City, everyone knew that Prince Zishu Nan of Qi and Princess Xu Mengyan were deeply in love and devoted to each other. Later, Prince Qi died in battle to protect the people of the city, burying his bones in Qi City. As spring and autumn turned, a hundred years of time passed in a flash. The legitimate daughter of the Daying Prime Minister's residence was born, and Prime Minister Xu Yi, looking at the baby girl in his arms, named her Xu Mengyan. Year after year thereafter, whenever Xu Mengyan encountered danger, there was always a lonely figure hidden in the dark, silently protecting her safety. Seeking dreams and truth, she finally realized that that figure was the loved one who crossed the years and whose obsession remained unbroken. Through the sea of people and endless twists and turns, two people whose hearts are tied together meet again in this life.