Thus far, Ryouta Sakamoto and Himiko have narrowly managed to survive 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 strongest opponent on the island, Ryouta is at a serious disadvantage. Not only is the man fearless, but also his movements are precisely calculated, and he possesses a superior athleticism that allows him to entrap his enemies. Just who is this guy?! As the action ramps up, it becomes apparent that playing solo spells one's doom!! The game progresses with speed as the players lay their bets on teaming up to survive!!