The saturated world economy has brought unprecedented economic depression to Asian countries. At the beginning of the new century, a country collapsed completely, with the total unemployment rate exceeding 15% and the national unemployed population10 million. People who lost confidence in their survival began to threaten innocent children. There are 800,000 children and students in China who refuse to go to school. School teachers were subjected to violence by students, and the number of people killed in the line of duty was as high as 1200. At this time, a new law was introduced. BR bill is the general name of education reform law in the new century. The so-called BR bill is to eliminate citizens' antipathy to school closure and despicable juvenile delinquency; In order to train young people to overcome all kinds of difficulties in adversity, so as to obtain indomitable survival ability; Let teenagers regain their rights from adults.

From the third grade of junior high school in China, a class is randomly selected every year to send students to a barren place with limited scope of action. Give each student a map, food and all kinds of weapons, and let them kill each other until there is only one left. The time limit is 3 days. Students must wear a special self-explosive collar that violates the regulations. During this period, students' murder, injury, possession of guns and other illegal acts are not restricted by law. This is the origin of all the blood and cruelty in the film. A delicate switchblade went through an argumentative girl's forehead. The next one to die is a boy who is very close to Qiyuan but is rejected by the teacher. A bomb tied to his neck blew his head off. Other students killed each other with bows and arrows, pickaxes and sickles. At the end of the film, when three surviving students have a direct conversation with Kitano Takeshi, Kitano lures Qiyuan to shoot himself with a water gun, trying to end his miserable and lonely life with Qiyuan's hand. After being shot, he gets up and answers his daughter's phone, which shows his dissatisfaction with her. Most of the film is shrouded in a suffocating atmosphere, and the theme of the film is pointed out at the end, which is also the reason why the film is full of vigor and hope: Qiyuan and Nakagawa escape from their respective families and embark on a pure and independent life path and rush to adulthood.