Seventeen-year-old Cheng Miaomiao and sixteen-year-old Cheng Yaya were born in the No. 1 Oil Extraction Plant of Linqi Oilfield, with three generations of their family working in the oilfield. Their father, Cheng Pengfei, is an ENT doctor, and their mother, Jia Daiyu, works in fleet logistics. The family moved from the northwest to the coastal base of Heping Town. In the late 1990s, Miaomiao, yearning for the outside world, planned an adventure to "welcome the return of Hong Kong" during the summer vacation of her first year of high school. She roped in her childhood friend Li Si and her best friend Hu Qiumin, but their plan failed from the start. Meanwhile, her 16-year-old brother, Cheng Yaya, went up the mountain for an archaeological expedition and was almost mistaken for a tomb raider. Their mother, Jia Daiyu, was extremely troubled, and the siblings began their chaotic high school journey. Miaomiao found herself in a friendship crisis with Li Si, while Yaya's class saw the transfer of Yuan Shanqing, the daughter of a wanted criminal. Yaya was the first to stand up and shield Yuan Shanqing from hostility from all sides. In the midst of dealing with changes and challenges, the children welcomed growth in their lives.