In 2021, Lin Beixing, approaching 30, works at a zoo in an animal suit and eagerly anticipates marrying Zhan Yu, whom she has loved since high school. Just before their wedding, he abruptly cancels, claiming he never loved her, prompting her to attempt various stunts to win him back. In a last-ditch effort, she asks him to revisit their old school in their high school attire, but accidentally deletes a message on her old 2G phone, sending her to a parallel past universe. There, she encounters the talented Zhang Wansen, who suffered a tragic fate in 2010, and discovers that she can return to that year by deleting more messages. As she attempts to change her past while growing closer to Zhang Wansen, she seeks a way to alter both their destinies.