In Beijing's Beijing Primary School, a fictional school, Class One Grade Five (五年级甲班) has more than 40 students. These students are cute, clever and have become Chinese Young Pioneers; except two students: Jiang Lin (江林), who is mischievous and not hard-working, and Yang Yongli (杨永丽), who is arrogant, anti-social and doesn't care about others.
On June 1, students get together with the home-bound People's Volunteer Army in Zhongshan Park. Volunteer Yang Zhiping (杨志平) notices that two students don't wear Red scarfs, which symbolize the Young Pioneers of the Chinese Communist Party. Before he leaves, he encourages the students to study hard, help each other, and try to become a model class. Student Liang Huiming (梁慧明) is touched by his words and tries to help the two, but they do not appreciate it. This make Liang feel sad. Classmates sympathize with Liang and lose faith in the two.
The head teacher Feng encourages students to have patience. Later, classmates invite Jiang Lin to do an oxygen experiment, to make him interested in studying. While Yang Yongli's foot is scalded, they helped her make up homework, so that she can take exams with the class. In classmates helping, Yang and Jiang were moved, they progress together in summer vacation.
After summer vacation, the class became to grade six. Jiang Lin and Yang Yongli become Young Pioneers for their progress.