Middle school girls Xiaobu (played by Li Lu) and Anqi (played by Yao Anqi) used to be an inseparable couple. The only two girls in the school who smoked, their relationship was as erratic and addictive as tobacco. They often shared their fantasies on the swings of the secret base until one day, they quarreled and stopped communicating. Xiaobu fell off her bicycle and met her future boyfriend, Case, who practiced boxing. They often played together with Xiaobu's friend Ami (played by Liao Qianhui). Xiaobu didn't know that on a boring summer afternoon, Case fell in love with Ami on the dance machine at first sight... Although Xiaobu no longer contacted Anqi, the memory of the latter often made her deeply emotional. From the past to the present, the knot of fate of these four young people has never been separated, and has always been entangled around them in an obscure way.