Thus far, Ryouta Sakamoto and Himiko have narrowly managed to stay alive on the cruel island battlefield of the survival game "BTOOOM!" with the aid of their BIMs and each other. But now, confronted by a man who just might be the toughest opponent on the island, Ryouta is at a serious disadvantage. The man fearless, his movements precisely calculated, and he possesses a superior athleticism with which he entraps his enemies. Just who is this guy?! As the action ramps up, it becomes apparent that going it solo spells one's doom, and the players lay their bets on teaming up to survive!!