A small-town girl, Chen Huan'er, moves with her family to a big city where she befriends Jing Xichi and Song Cong. From high school to college and eventually to graduation, the three of them experience life's major milestones together. Their days are filled with quiet yet meaningful moments such as studying, weekend outings, sports meets, and book exchanges. They also go through the bittersweet feelings of secret crushes, the frustration of shattered dreams, the helplessness of family upheavals, and the sorrow of losing a loved one for the first time. Through every challenge and hardship, they support one another as they grow from naive teenagers into adults who learn to find their place in the world. In the end, they become versions of themselves that are completely different from what they once imagined in high school but still just as fulfilling. Most importantly, no matter how much life changes, they always stay by each other's side.