The story is set in an alternative timeline in Japan dubbed as Republic of Greater East Asia. One class of high school students went on a field trip until they were put to sleep and later, woke up in a “classroom” with metal collars around their necks.
They realize that they have been selected in “The Program” (aka Battle Royale Act) in which they are forced to kill each other in the island until one survives. The collar placed around their necks has a bomb in it and if anyone attempts to remove it or enter the forbidden zone, the collar will explode.
The protagonist is Shuya Nanahara, who is an aspiring rock musician (Rock music is banned by the government in this story). He and Noriko Nakagawa, a girl whom his best friend, Yoshitoki Kuninobu (who was killed early by the Program instructor before the game begins), had a crush on, tries to survive in order to escape the Program with the help from Shogo Kawada, a transfer student with a mysterious past.
Other characters include Mitsuko Souma, who is very beautiful but disturbing with bipolar tendencies, Shinji Mimura, a basketball player and skilled hacker, Hiroki Sugimura, a martial artist and Kazuo Kiriyama, the antagonist with a killing spree.
The program instructor differs in all three versions. In the novel, his name is Kinpatsu Sakamochi, who is a government employee. In the manga, his name is Yonemi Kamon], also a government employee. And in the first film, his name is Kitano, who is the class advisor of Shuya’s class. In the film, he has an affection on Noriko which he treats her as a surrogate daughter. He also has a daughter (who became the protagonist in the second film) but their relationship is strained.
The novel is controversial at first but it gain wide recognition. As a result, it is adapted into a film and later a manga, which both has sequels.
The film version is quite different in which most of the characters’ development is repressed. The deaths of certain characters differ. But the adaptation is fair enough. But its sequel, Battle Royale II: Requiem, is terrible. Some of the actors are over exaggerating and the story is quite confusing (because they mixed it with mumbo jumbo stuff about the US bombing their enemies).
The manga version follows similarly to the the novel except that the deaths are more gruesome than you can ever imagine (or somewhat unrealistic, clue: Shinji’s death and Kazuo’s death). Oh, and in the English translation, they made the “the Program” as a reality-based show instead by the government which can be a big facepalm. I haven’t read its sequel though it is said to be inspired by the 2nd film.
There is even an attempt to make a Hollywood remake of the novel except that due to the Virginia Tech massacre or even Columbine shootings, I doubt that anyone can ever made a Hollywood movie of it.
I heard that the author of the novel is currently doing a sequel of it. I guess we might hear what happened to survivors. But that’s another story.