 In the near future, when the society of Japan is crumbling, forty-two students find that their field trip is actually a military-sponsored game known as "Battle Royale". The kids  sadistic former teacher Kitano sends them to an isolated island and gives them three days to kill each other until only one remains. Two of the kids, Shuya and Noriko, stay together and further develop their already-formed bond. A transfer student, Kawada, sympathizes with the two and chooses to help them. Others develop a plan to bring down the military game, try to find their crush before they die, or lose their minds and go on killing sprees.