From Tokyopop:
In the future, random Jr. High School classes are chosen to compete in a game called Battle Royale. The rules: only one student can survive after 3 days on an island or else they all perish. Weapons are handed out and each student is sent out into the field alone and unprepared for the horror that awaits them. The classmates turn upon themselves in a battle for survival, treaties are made and broken, and former friends become foes as the relentless countdown continues. Amid the betrayals and rising body count, two classmates confess their love for each other and swear to survive this deadly game together.

Note: An English-language release of the collected volumes, published in the United States, Canada, and United Kingdom by Tokyopop, was extensively rewritten by Keith Giffen, whose script does not completely follow the original manga. This adaptation makes several changes to the plot. Most notably claiming "the program" is a reality TV show and changing the time that the story is set in by almost 10 years, both of which are contradicted in later volumes.