Shen Heng, who possesses vast chronological experience and perspective, chooses a low-key, ordinary life, experiencing the human world in the identity of a delivery driver. A centenarian recognizes him and entrusts him with caring for her granddaughter, Gu Nianchu. Through this, Shen Heng steps into this prominent family, witnessing internal ideological divisions within the family. As past experiences gradually unfold, someone obsessively explores the mysteries related to longevity, and a game surrounding secrets slowly emerges. Shen Heng adheres to his original intention and guards those around him.