The story tells about An Jing (Zhang Zimu), a high school girl living in Songxi, a small town. In the process of independently writing a campus novel called Goodbye, Seventeen, she transformed into the protagonists of three stories, Anna, An Qi, and An Jing, and traveled through different time and space to meet different classmates, including the timid top student Han Yun (Chen Pinyan), the warm senior Chu Yu (Shi Mingze), and the twin brothers Cheng Haoxuan (Wang Jiahui) and Cheng Haoyu (Shi An) with very different personalities. The classmates went from strangers to familiarity, found friendship in the tense high school life, and went through the bitterness of adolescence together, finally ushering in the transformation moment of 17 years old.