Huang Yuxuan and Li Ziwei experience a profound connection through a shared dream, where they encounter a mysterious figure in the rain and enjoy music in a record shop. However, upon waking, they feel like strangers. Their fates intertwine in 2009 when Huang Yuxuan meets Li Ziwei, whom she recognizes from her dreams, at a beverage shop where she works part-time. Intrigued by Yuxuan, Ziwei feels an instant connection, and they quickly grow closer despite being strangers.
As their romance blossomed, Yuxuan recounts a childhood memory of getting lost in Tainan, where she was guided home by an older boy – who turns out to be Ziwei. This revelation deepens their bond, and they celebrate their love by spending New Year’s Eve together in 2010, eventually becoming a couple. By 2014, they take their relationship to the next level by moving in together, yet in 2017, Yuxuan is offered a job transfer to Shanghai, threatening their stability.
Faced with the heart-wrenching decision to part ways, Ziwei reassures Yuxuan that he will respect her choice. In a poignant moment in a Shanghai hotel, Yuxuan reflects on their chats, realizing that the last time she heard from Ziwei was in 2014. Grief-stricken, she learns that Ziwei tragically died in a fall on July 10, 2014, leading her to live in denial, as she pretended he was still alive.
The plot thickens when Yuxuan receives an anonymous package at her workplace, containing a Walkman and a cassette tape of Wu Bai’s album The End of Love. As she listens to "Last Dance," she unexpectedly finds herself inhabiting the body of another girl named Chen Yunru and realizes she has traveled back to July 8, 2014, just before Ziwei's fatal incident. Rushing to find him, she embraces Ziwei, who is puzzled by her sudden emotional outburst.
While in Yunru's body, Yuxuan attempts to explain her situation, claiming she is actually Yuxuan from 2017. However, Ziwei and Mo Junjie misunderstand her situation, believing that Yunru has simply changed drastically. Determined to save Ziwei, Yuxuan watches over him closely, but her distraction leads to disastrous consequences. As a chain of events unfolds, both she and Ziwei find themselves in a perilous situation on the rooftop of an abandoned building, leading to a tragic cycle.
Afterward, Yuxuan’s spirit returns to 2017, where she meets Mo Junjie and discovers another “Li Ziwei” who is actually Wang Quansheng, who has been inhabited by the spirit of Li Ziwei from 2017. Quansheng shares that their timelines diverge, revealing that in another alternate sequence of events, both Yuxuan and Yunru fell to their deaths. The story then follows the intertwining experiences of these characters across different timelines as they seek a way to save each other.
In 2017, together with Quansheng and Junjie, Yuxuan searches for Yunru, who is surprisingly still alive, only to uncover that she is married to Yang Hao, Yuxuan’s supervisor in Shanghai. After learning that Yunru is in a coma following a tragic miscarriage, Yuxuan discovers from Yang Hao about the potential of time travel through a special cassette tape. Regretting the twisted fates, they reveal that it was the tape that allowed Yunru to time travel back into Yuxuan’s life, setting off the events leading to the tragedies that are about to unfold.
Unbeknownst to Yuxuan, Yunru grapples with feelings of guilt and makes a tragic decision that will lead to a cycle of heartbreak. The narrative then shifts back to 2014, capturing the moment when both Yuxuan and Ziwei fall, culminating in their tragic end. In the aftermath of Yuxuan’s departure from existence, Yunru records everything in her diary in a bid to preserve their memories.
Years later, she encounters Quansheng, who is dealing with his personal struggles, leading to their bond and mutual support. In time, with Yunru’s encouragement, Quansheng decides to let go of the painful memories that the tape encapsulated. Together, they embark on a journey to destroy the very tape that caused their suffering.
After much emotional turmoil, Quansheng arranges a meet-up with Yunru at a record fair, where he apologizes for not fulfilling his promise to her. In a heartwarming moment, they listen to "Last Dance" together, which rekindles their shared memories.
Finally, Yuxuan awakens, pondering whether her experiences were nothing more than a vivid dream; upon turning and glimpsing Ziwei next to her, their entwined fingers reveal a reality filled with love. In a continuation of the story, events unfold in 2019, where Yuxuan and Ziwei plan to celebrate her birthday after a thoughtful video call from him, culminating in a surprise marriage proposal, embodying hope and a second chance.
