The protagonist, a university senior who discovers her parents have been meticulously tracking every expense spent on her since birth, totaling 248,000 yuan. She confronts her emotionally neglectful parents, packs her suitcase, and leaves home during the Spring Festival to return to school for her graduation thesis. On the high-speed train, she falls into a tunnel and time-travels, her body reverting to that of a two-to-three-year-old child. She is calm, resolute, and deeply hurt by her family's favoritism toward her brother.
