At the end of Junior Class, Mike founded a technology company, resigned from Microsoft and concentrated on studying the financial curve at home. Wu lived a dull life and became a scholar studying rural environmental issues. Teacher Zhou resigned from school and was never heard from. The egg at the end of the film also suggests that Jiang Yilin became a dance teacher and Qin Hai became a fitness instructor.

The film mainly tells the story of five talented teenagers in 1998, Mike (Wang Dongxin), Fang Houzheng (Li Jiaqi), Wu Mo (Dong Zijian), Wang Dafa (Liu Xilong) and Zhou Lan (Zhou Dongyu), who were selected by their teachers (Sun) and goggles to form the "World Mathematics Competition".

Xiao Yangshou, who was born in the "Youth Class" of An Jiaotong University, filmed his own personal experience, and all the characters were based on reality. As a well-known editor, Xiao Yang had the opportunity to be a director, but he was dormant for seven years, precipitating his heart, in order to make a work worthy of the audience and his own. Youth Class became Shawn's directorial debut.

Many years ago, when Xiao Yang told me about his past life in Class 3 of Grade 3, he was intrigued and decided to invest in making films with the theme of genius. The imagination of the genius world itself constitutes a huge drama.