Battle royale - Koushun Takami

The Program is a brutal military experiment that pits junior high students against each other every year in a brutal battle to the death. Most of the students from Shiroiwa Junior High scatter as soon as they reach the remote island where they must participate in the latest round of the Program. But Yukie Utsumi and five of her friends lock themselves in the lighthouse, clinging to a desperate hope of survival. They all trust each other, but they also know that only one can survive the Battle Royale… A graphic novel side story of the bestselling novel Battle Royale.