Two years after Qihara Qiuya and Nakagawa Noriko got away from BR and left the isolated island, the human world has entered the age of terrorism. The capital was bombed into rubble under the hands of "terrorists" from anti-BR countries. The government authorities judged the perpetrator of this incident as Shichihara and started an international wanted for him.
One year after the collapse of the capital, Qiyuan, as the leader of the anti-BR organization "wild seven", issued a declaration of war to all adults. In order to kill Qiyuan, the adults planned a new game in the name of anti-terrorism justice-the special law for counter-terrorism countermeasures in the new century, commonly known as BR Ⅱ.
Against this background, one day, unscrupulous teenagers from all over the country, as well as 42 children from the 3-year group B of Luzhizhai Middle School, who were truant students, fell on their way to the ski school during the Christmas holiday trip. For the army's hijacking goal, he was kidnapped by all his staff to an isolated island. When they were ordered to change into military uniforms and escorted them to a huge military camp, their instructor RIKI appeared. "There is no exception in the entire class and will be a participant in this BRⅡ", RIKI announced the reasons for the kidnapping to the students who had fallen into chaos and explained the rules of the BRⅡ game.
The children struggled to slide the violently shaking small boats, their bodies wet from the surf, doing everything they could to head towards the isolated island desperately. However, when they were finally about to land, the terrorist attack began. Light bombs were intertwined, and mortars continued to explode on the water. In the face of such a sudden situation, the students with mixed consternation had only the power to dodge, not the preparation to fight back. Some people were pierced by bullets like a honeycomb, while others were hit by oncoming shells and flew high. The members of Wild Seven did not know that the people in military uniforms who came to attack Qiyuan were actually a group of middle school students, so they carried all their beliefs in declaring war against the BR country and launched an attack to the death. The students who finally landed on the ground amidst the rain of bullets and the flames of the explosion, they wanted to retreat temporarily because the ammunition was exhausted. However, the artillery fire continued, leaving nowhere to hide. At this moment in the battle, the students with only 26 members left finally realized that they were already desperate. So only resolutely took up the weapon and was involved in another war game in which the children were conspired by adults to kill each other .