In the fifteenth year of Jian'an, Zhou Yu, the great commander of Jiangdong, dies young. Grieving the loss of such a brilliant talent, Zhuge Liang uses the Big Dipper formation to help him transmigrate through time and be reborn. Under the assumed name Zhou Muyu, he becomes a gifted pianist in modern society. Meanwhile, Xiao Qiao is reborn as Qiao Yuwei, a lively, cheerful modern college student who loves music but has no memories of her past life. Her parents are prominent figures in the business world. They have high hopes for her and want her to inherit the family business and marry a wealthy young man of equal standing.
At a music competition, Zhou Muyu meets Qiao Yuwei and feels an inexplicable sense of familiarity. After a series of twists and turns, he gradually realizes that Qiao Yuwei is Xiao Qiao's reincarnation. He decides to help her recover her memories of her past life, and composes a classical piece, A Love Across a Thousand Years, for that purpose. As the two spend more time together, Qiao Yuwei begins dreaming of hazy scenes and develops feelings for Zhou Muyu that she can't put into words.
However, Qiao Yuwei's roommate, Cao Wanhui, has always been jealous of her talent and happiness. She secretly steals Qiao Yuwei's unfinished composition and takes advantage of Zhou Muyu's trust, leading him to believe that she wrote it. Cao Wanhui uses this opportunity to get closer to Zhou Muyu and tries to take Qiao Yuwei's place in his heart.
With Zhou Muyu's help, Qiao Yuwei finally recovers the memories of her past life. She finally understands that her bond with Zhou Muyu spans a thousand years. She bravely pursues her love, and the two end up together.
